Title 49—Transportation--Volume 1
PART 571—FEDERAL MOTOR VEHICLE SAFETY STANDARDS
§ 571.119   Standard No. 119; New pneumatic tires for motor vehicles with a GVWR of more than 4,536 kilograms (10,000 pounds), specialty tires, and tires for motorcycles.
S1. Scope. This standard establishes performance and marking requirements for tires for use on motor vehicles with a GVWR of more than 4,536 kilograms (10,000 pounds), specialty tires, and tires for motorcycles.
S2. Purpose. The purpose of this standard is to provide safe operational performance levels for tires used on motor vehicles with a GVWR of more than 10,000 pounds, trailers, and motorcycles, and to place sufficient information on the tires to permit their proper selection and use.
S3. Application. This standard applies to:
(a) New pneumatic tires for use on motor vehicles with a GVWR of more than 4,536 kilograms (10,000 pounds) manufactured after 1948;
(b) New pneumatic light truck tires with a tread depth of 18/32 inch or greater, for use on motor vehicles with a GVWR of 4,536 kilograms (10,000 pounds) or less manufactured after 1948;
(c) Tires for use on special-use trailers (ST, FI and 8-12 rim or lower diameter code); and
(d) Tires for use on motorcycles manufactured after 1948.
S4. Definitions. All terms defined in the Act and the rules and standards issued under its authority are used as defined therein.
Light truck tire means a tire designated by its manuafacturer as primarily intended for use on lightweight trucks or multipurpose passenger vehicles.
Model rim assembly means a test device that (a) includes a rim which conforms to the published dimensions of a commercially available rim, (b) includes an air valve assembly when used for testing tubeless tires or an innertube and flap (as required) when used for testing tubetype tires, and (c) undergoes no permanent rim deformation and allows no loss of air through the portion that it comprises of the tire-rim pressure chamber when a tire is properly mounted on the assembly and subjected to the requirements of this standard.
S5. Tire and rim matching information.
S5.1 Each manufacturer of tires shall ensure that a listing of the rims that may be used with each tire that he produces is provided to the public. For purposes of this section each rim listing shall include dimensional specifications and a diagram of the rim. However a listing compiled in accordance with paragraph (a) of this section need not include dimensional specifications or a diagram of a rim if the rim's dimensional specifications and diagram are contained in each listing published in accordance with paragraph (b) of this standard. The listing shall be in one of the following forms:
(a) Listed by manufacturer name or brand name in a document furnished to dealers of the manufacturer's tires, to any person upon request, and in duplicate to: Docket Section, National Highway Traffic Safety Administration, 400 Seventh Street SW., Washington, DC 20590; or
(b) Contained in publications, current at the date of manufacture of the tire or any later date, of at least one of the following organizations:
S5.2 Information contained in a publication specified in S5.1(b) which lists general categories of tires and rims by size designation, type of construction, and/or intended use, shall be considered to be manufacturer's information pursuant to S5.1 for the listed tires, unless the publication itself or specific information provided according to S5.1(a) indicates otherwise.
S6. Requirements. Each tire shall be capable of meeting any of the applicable requirements set forth below, when mounted on a model rim assembly corresponding to any rim designated by the tire manufacturer for use with the tire in accordance with S5. However, a particular tire need not meet further requirements after having been subjected to and met the endurance test (S6.1), strength test (S6.2), or high speed performance test (S6.3).
S6.1 Endurance.
S6.1.1 Prior to testing in accordance with the procedures of S7.2, a tire shall exhibit no visual evidence of tread, sidewall, ply, cord, innerliner, or bead separation, chunking, broken cords, cracking, or open splices.
S6.1.2 When tested in accordance with the procedures of S7.2:
(a) There shall be no visual evidence of tread, sidewall, ply, cord, innerliner, or bead separation, chunking, broken cords, cracking, or open splices.
(b) The tire pressure at the end of the test shall be not less than the initial pressure specified in S7.2(a).
S6.2 Strength. When tested in accordance with the procedures of S7.3 a tire's average breaking energy value shall be not less than the value specified in Table II for that tire's size and load range.
S6.3 High speed performance. When tested in accordance with the procedures of S7.4, a tire shall meet the requirements set forth in S6.1.1 and S6.1.2(a) and (b). However, this requirement applies only to motorcycle tires and to non-speed-restricted tires of nominal rim diameter code 14.5 or less marked load range A, B, C, or D.
S6.4 Treadwear indicators. Except as specified in this paragraph, each tire shall have at least six treadwear indicators spaced approximately equally around the circumference of the tire that enable a person inspecting the tire to determine visually whether the tire has worn to a tread depth of 1.6 mm (one-sixteenth of an inch). Tires with a rim diameter code of 12 or smaller shall have at least three such treadwear indicators. Motorcycle tires shall have at least three such indicators which permit visual determination that the tire has worn to a tread depth of 0.8 mm (one-thirty-second of an inch).
S6.5 Tire markings. Except as specified in this paragraph, each tire shall be marked on each sidewall with the information specified in paragraphs (a) through (j) of this section. The markings shall be placed between the maximum section width (exclusive of sidewall decorations or curb ribs) and the bead on at least one sidewall, unless the maximum section width of the tire is located in an area which is not more than one-fourth of the distance from the bead to the shoulder of the tire. If the maximum section width falls within that area, the markings shall appear between the bead and a point one-half the distance from the bead to the shoulder of the tire, on at least one sidewall. The markings shall be in letters and numerals not less than 2 mm (0.078 inch) high and raised above or sunk below the tire surface not less that 0.4 mm (0.015 inch), except that the marking depth shall be not less than 0.25mm (0.010 inch) in the case of motorcycle tires. The tire identification and the DOT symbol labeling shall comply with part 574 of this chapter. Markings may appear on only one sidewall and the entire sidewall area may be used in the case of motorcycle tires and recreational, boat, baggage, and special trailer tires.
(a) The symbol DOT, which shall constitute a certification that the tire conforms to applicable Federal motor vehicle safety standards. This symbol may be marked on only one sidewall.
(b) The tire identification number required by part 574 of this chapter. This number may be marked on only one sidewall.
(c) The tire size designation as listed in the documents and publications designated in S5.1.
(d) The maximum load rating and corresponding inflation pressure of the tire, shown as follows:
(Mark on tires rated for single and dual load): Max load single ____kg (____lb) at ____kPa (____psi) cold. Max load dual ____kg (____lb) at ____kPa (____psi) cold.
(Mark on tires rated only for single load): Max load ____kg (____lb) at ____kPa (____psi) cold.
(e) The speed restriction of the tire, if 90 km/h (55 mph) or less, shown as follows:
(f) The actual number of plies and the composition of the ply cord material in the sidewall and, if different, in the tread area;
(g) The words “tubeless” or “tube type” as applicable.
(h) The word “regroovable” if the tire is designed for regrooving.
(i) The word “radial” if a radial tire.
(j) The letter designating the tire load range.
S6.6 Maximum load rating. If the maximum load rating for a particular tire size is shown in one or more of the publications described in S5.1(b), each tire of that size designation shall have a maximum load rating that is not less than the published maximum load rating, or if there are differing published ratings for the same tire size designation, not less than the lowest published maximum load rating for the size designation.
S7. Test procedures.
S7.1 General conditions.
S7.1.1 The tests are performed using an appropriate new tube, tube valve and flap assembly (as required) that allows no loss of air for testing of tube-type tires under S7.2, S7.3, and S7.4, and tubeless tires under S7.3.
S7.1.2 The tire must be capable of meeting the requirements of S7.2 and S7.4 when conditioned to a temperature of 35 °C (95 °F) for 3 hours before the test is conducted, and with an ambient temperature maintained at 35 °C (95 °F) during all phases of testing. The tire must be capable of meeting the requirements of S7.3 when conditioned at a temperature of 21 °C (70 °F) for 3 hours before the test is conducted.
S7.2 Endurance. (a) Mount the tire on a model rim assembly and inflate it to the inflation pressure corresponding to the maximum load rating marked on the tire. Use a single maximum load value when the tire is marked with both single and dual maximum load.
(b) After conditioning the tire-rim assembly in accordance with S7.1.2, adjust the tire pressure to that specified in (a) immediately before mounting the tire rim assembly.
(c) Mount the tire-rim assembly on an axle and press it against a flat-faced steel test wheel that is 1708 mm (67.23 inches) in diameter and at least as wide as the tread of the tire.
(d) Apply the test load and rotate the test wheel as indicated in Table III for the type of tire tested conducting each successive phase of the test without interruption.
(e) Immediately after running the tire the required time, measure the tire inflation pressure. Remove the tire from the model rim assembly, and inspect the tire.
S7.3 Strength. (a) Mount the tire on a model rim assembly and inflate it to the pressure corresponding to the maximum load, or maximum dual load where there is both a single and dual load marked on the tire. If the tire is tubeless, a tube may be inserted to prevent loss of air during the test in the event of puncture.
(b) After conditioning the tire-rim assembly in accordance with S7.1.2, adjust the tire pressure to that specified in (a).
(c) Force a cylindrical steel plunger, with a hemispherical end and of the diameter specified in Table I for the tire size, perpendicularly into a raised tread element as near as possible to the centerline of the tread, at a rate of 50 mm (2 inches) per minute, until the tire breaks or the plunger is stopped by the rim.
(d) Record the force and the distance of penetration just before the tire breaks, or if it fails to break, just before the plunger is stopped by the rim.
(e) Repeat the plunger application at 72° intervals around the circumference of the tire, until five measurements are made. However, in the case of tires of 12 inch rim diameter code or smaller, repeat the plunger application at 120° intervals around the circumference of the tire, until three measurements are made.
(f) Compute the breaking energy for each test point by one of the two following formulas:
(1) W = [(F × P)/2] × 10 −3
(2) W = (F × P)/2
(g) Determine the average breaking energy value for the tire by computing the average of the values obtained in accordance with paragraph (f).
S7.4 High speed performance. (a) Perform steps (a) through (c) of S7.2.
(b) Apply a force of 88 percent of the maximum load rating marked on the tire (use single maximum load value when the tire is marked with both single and dual maximum loads), and rotate the test wheel at 250 rpm for 2 hours.
(c) Remove the load, allow the tire to cool to 35 °C (95 °F), and then adjust the pressure to that marked on the tire for single tire use.
(d) Reapply the same load, and without interruption or readjustment of inflation pressure, rotate the test wheel at 375 rpm for 30 minutes, then at 400 rpm for 30 minutes, and then at 425 rpm for 30 minutes.
(e) Immediately after running the tire the required time, measure the tire inflation pressure. Remove the tire from the model rim assembly, and inspect the tire.
Table I—Strength Test Plunger Diameter
Table II—Minimum Static Breaking Energy
[Joules (J) and Inch-Pounds (in-lb)]
Note: For rayon cord tires, applicable energy values are 60 percent of those in table.
Table III—Endurance Test Schedule
a 4 hours for tire sizes subject to high speed requirements S6.3.
b 6 hours for tire sizes subject to high speed requirements S6.3.
§ 571.120   Tire selection and rims and motor home/recreation vehicle trailer load carrying capacity information for motor vehicles with a GVWR of more than 4,536 kilograms (10,000 pounds).
S1. Scope. This standard specifies tire and rim selection requirements, rim marking requirements and motor home/recreation vehicle trailer load carrying capacity information.
S2. Purpose. The purpose of this standard is to provide safe operational performance by ensuring that vehicles to which it applies are equipped with tires of adequate size and load rating and with rims of appropriate size and type designation, and by ensuring that consumers are informed of motor home/recreation vehicle trailer load carrying capacity.
S3. Application. This standard applies to motor vehicles with a gross vehicle weight rating (GVWR) of more than 4,536 kilograms (10,000 pounds and motorcycles, to rims for use on those vehicles, and to non-pneumatic spare tire assemblies for use on those vehicles.
S4. Definitions. All terms defined in the Act and the rules and standards issued under its authority are used as defined therein.
Rim base means the portion of a rim remaining after removal of all split or continuous rim flanges, side rings, and locking rings that can be detached from the rim.
Rim size designation means rim diameter and width.
Rim diameter means nominal diameter of the bead seat.
Rim width means nominal distance between rim flanges.
Rim type designation means the industry or manufacturer's designation for a rim by style or code.
Weather side means the surface area of the rim not covered by the inflated tire.
S5. Requirements.
S5.1 Tire and rim selection.
S5.1.1 Except as specified in S5.1.3, each vehicle equipped with pneumatic tires for highway service shall be equipped with tires that meet the requirements of § 571.109, § 571.119 or § 571.139, and rims that are listed by the manufacturer of the tires as suitable for use with those tires, in accordance with S4.4 of § 571.109 or S5.1 of § 571.119, as applicable, except that vehicles may be equipped with a non-pneumatic spare tire assembly that meets the requirements of § 571.129, New non-pneumatic tires for passenger cars, and S8 of this standard. Vehicles equipped with such an assembly shall meet the requirements of S5.3.3, S7, and S9 of this standard.
S5.1.2 Except in the case of a vehicle which has a speed attainable in 3.2 kilometers of 80 kilometers per hour or less, the sum of the maximum load ratings of the tires fitted to an axle shall be not less than the gross axle weight rating (GAWR) of the axle system as specified on the vehicle's certification label required by 49 CFR part 567. Except in the case of a vehicle which has a speed attainable in 2 miles of 50 mph or less, the sum of the maximum load ratings of the tires fitted to an axle shall be not less than the gross axle weight rating (GAWR) of the axle system as specified on the vehicle's certification label required by 49 CFR part 567. If the certification label shows more than one GAWR for the axle system, the sum shall be not less than the GAWR corresponding to the size designation of the tires fitted to the axle. If the size designation of the tires fitted to the axle does not appear on the certification label, the sum shall be not less than the lowest GAWR appearing on the label. When a passenger car tire is installed on a multipurpose passenger vehicle, truck, bus, or trailer, the tire's load rating shall be reduced by dividing by 1.10 before calculating the sum (i.e., the sum of the load ratings of the tires on each axle, when the tires' load carrying capacity at the recommended tire cold inflation pressure is reduced by dividing by 1.10, must be appropriate for the GAWR).
S5.1.3 In place of tires that meet the requirements of Standard No. 119, a truck, bus, or trailer may at the request of a purchaser be equipped at the place of manufacture of the vehicle with retreaded or used tires owned or leased by the purchaser, if the sum of the maximum load ratings meets the requirements of S5.1.2. Used tires employed under this provision must have been originally manufactured to comply with Standard No. 119, as evidenced by the DOT symbol.
S5.2 Rim marking. Each rim or, at the option of the manufacturer in the case of a single-piece wheel, wheel disc shall be marked with the information listed in paragraphs (a) through (e) of this paragraph, in lettering not less than 3 millimeters high, impressed to a depth or, at the option of the manufacturer, embossed to a height of not less than 0.125 millimeters. The information listed in paragraphs (a) through (c) of this paragraph shall appear on the weather side. In the case of rims of multi piece construction, the information listed in paragraphs (a) through (e) of this paragraph shall appear on the rim base and the information listed in paragraphs (b) and (d) of this paragraph shall also appear on each other part of the rim.
(a) A designation which indicates the source of the rim's published nominal dimensions, as follows:
(1) “T” indicates The Tire and Rim Association.
(2) “E” indicates The European Tyre and Rim Technical Organisation
(3) “J” indicates Japan Automobile Tire Manufacturers' Association, Inc.
(4) “D” indicates Deutsche Industrie Norm.
(5) “B” indicates British Standards Institution.
(6) “S” indicates Scandinavian Tire and Rim Organization.
(7) “A” indicates The Tyre and Rim Association of Australia.
(8) “N” indicates an independent listing pursuant to S4.4.1(a) of Standard No. 109 or S5.1(a) of Standard No. 119.
(b) The rim size designation, and in case of multipiece rims, the rim type designation. For example: 20 × 5.50, or 20 × 5.5.
(c) The symbol DOT, constituting a certification by the manufacturer of the rim that the rim complies with all applicable motor vehicle safety standards.
(d) A designation that identifies the manufacturer of the rim by name, trademark, or symbol.
(e) The month, day and year or the month and year of manufacture, expressed either numerically or by use of a symbol, at the option of the manufacturer. For example:
“September 4, 1976” may be expressed numerically as:
“September 1976” may be expressed as:
(1) Any manufacturer that elects to express the date of manufacture by means of a symbol shall notify NHTSA in writing of the full names and addresses of all manufacturers and brand name owners utilizing that symbol and the name and address of the trademark owner of that symbol, if any. The notification shall describe in narrative form and in detail how the month, day, and year or the month and year are depicted by the symbol. Such description shall include an actual size graphic depiction of the symbol, showing and/or explaining the interrelationship of the component parts of the symbol as they will appear on the rim or single piece wheel disc, including dimensional specifications, and where the symbol will be located on the rim or single piece wheel disc. The notification shall be received by NHTSA at least 60 calendar days prior to first use of the symbol. The notification shall be mailed to the Office of Vehicle Safety Compliance, National Highway Traffic Safety Administration, 400 Seventh Street SW., Washington, DC 20590. All information provided to NHTSA under this paragraph will be placed in the public docket.
(2) Each manufacturer of wheels shall provide an explanation of its date of manufacture symbol to any person upon request.
S5.3 Each vehicle shall show the information specified in S5.3.1 and S5.3.2 and, in the case of a vehicle equipped with a non-pneumatic spare tire, the information specified in S5.3.3, in the English language, lettered in block capitals and numerals not less than 2.4 millimeters high and in the format set forth following this paragraph. This information shall appear either—
(a) After each GAWR listed on the certification label required by § 567.4 or § 567.5 of this chapter; or at the option of the manufacturer,
(b) On the tire information label affixed to the vehicle in the manner, location, and form described in § 567.4 (b) through (f) of this chapter as appropriate of each GVWR-GAWR combination listed on the certification label.
S5.3.1 Tires. The size designation (not necessarily for the tires on the vehicle) and the recommended cold inflation pressure for those tires such that the sum of the load ratings of the tires on each axle (when the tires' load carrying capacity at the specified pressure is reduced by dividing by 1.10, in the case of a tire subject to FMVSS No. 109) is appropriate for the GAWR as calculated in accordance with S5.1.2.
S5.3.2. Rims. The size designation and, if applicable, the type designation of Rims (not necessarily those on the vehicle) appropriate for those tires.
S5.3.3 The non-pneumatic tire identification code, with which that assembly is labeled pursuant to S4.3(a) of § 571.129.
S6. Load Limits for Non-Pneumatic Spare Tires. The highest vehicle maximum load on the tire for the vehicle shall not be greater than the load rating for the non-pneumatic spare tire.
S7 Labeling Requirements for Non-Pneumatic Spare Tires or Tire Assemblies. Each non-pneumatic tire or, in the case of a non-pneumatic tire assembly in which the non-pneumatic tire is an integral part of the assembly, each non-pneumatic tire assembly shall include, in letters or numerals not less than 4 millimeters high, the information specified in paragraphs S7 (a) and (b). The information shall be permanently molded, stamped, or otherwise permanently marked into or onto the non-pneumatic tire or non-pneumatic tire assembly, or shall appear on a label that is permanently attached to the tire or tire assembly. If a label is used, it shall be subsurface printed, made of material that is resistant to fade, heat, moisture and abrasion, and attached in such a manner that it cannot be removed without destroying or defacing the label on the non-pneumatic tire or tire assembly. The information specified in paragraphs S7 (a) and (b) shall appear on both sides of the non-pneumatic tire or tire assembly, except, in the case of a non-pneumatic tire assembly which has a particular side that must always face outward when mounted on a vehicle, in which case the information specified in paragraphs S7 (a) and (b) shall only be required on the outward facing side. The information shall be positioned on the tire or tire assembly such that it is not placed on the tread or the outermost edge of the tire and is not obstructed by any portion of any non-pneumatic rim or wheel center member designated for use with that tire in this standard or in Standard No. 129.
(a) FOR TEMPORARY USE ONLY; and
(b) MAXIMUM 80 KM/H (50 M.P.H.).
S8. Requirements for Vehicles Equipped with Non-Pneumatic Spare Tire Assemblies
S8.1 Vehicle Placarding Requirements. A placard, permanently affixed to the inside of the spare tire stowage area or equally accessible location adjacent to the non-pneumatic spare tire assembly, shall display the information set forth in S7 in block capitals and numerals not less than 6 millimeters high preceded by the words “IMPORTANT—USE OF SPARE TIRE” in letters not less than 9 millimeters high.
S8.2 Supplementary Information. The owner's manual of the vehicle shall contain, in writing in the English language and in not less than 10 point type, the following information under the heading “IMPORTANT—USE OF SPARE TIRE”:
(a) A statement indicating the information related to appropriate use for the non-pneumatic spare tire including at a minimum the information set forth in S8 (a) and (b) and either the information set forth in S5.3.6 or a statement that the information set forth in S5.3.6 is located on the vehicle placard and on the non-pneumatic tire;
(b) An instruction to drive carefully when the non-pneumatic spare tire is in use, and to install the proper pneumatic tire and rim at the first reasonable opportunity; and
(c) A statement that operation of the vehicle is not recommended with more than one non-pneumatic spare tire in use at the same time.
S9 Non-Pneumatic Rims and Wheel Center Members
S9.1 Non-Pneumatic Rim Requirements. Each non-pneumatic rim that is part of a separable non-pneumatic spare tire assembly shall be constructed to the dimensions of a non-pneumatic rim that is listed pursuant to S4.4 of § 571.129 for use with the non-pneumatic tire, designated by its non-pneumatic tire identification code, with which the vehicle is equipped.
S9.2 Wheel Center Member Requirements. Each wheel center member that is part of a separable non-pneumatic spare tire assembly shall be constructed to the dimensions of a wheel center member that is listed pursuant to S4.4 of § 571.129 for use with the non-pneumatic tire, designated by its non-pneumatic tire identification code, with which the vehicle is equipped.
S10. Each motor home and recreation vehicle (RV) trailer must meet the applicable requirements in S10.
S10.1 On motor homes, the sum of the gross axle weight ratings (GAWR) of all axles on the vehicle must not be less than the gross vehicle weight rating (GVWR).
S10.2 On RV trailers, the sum of the GAWRs of all axles on the vehicle plus the vehicle manufacturer's recommended tongue weight must not be less than the GVWR. If tongue weight is specified as a range, the minimum value must be used.
S10.3 The tires on each motor home and RV trailer at first retail sale must be the same size as the tire size on the labeling required by S5.3.
S10.4 Each motor home and RV trailer single stage or final stage manufacturer must affix either a motor home occupant and cargo carrying capacity (OCCC) label (Figure 1) or a RV trailer cargo carrying capacity (CCC) label (Figure 2) to its vehicles that meets the following criteria:
S10.4.1 The RV load carrying capacity labels (Figures 1 and 2) must be legible, visible, moisture resistant, presented in the English language, have a minimum print size of 2.4 millimeters ( 3/32 inches) high and be printed in black print on a yellow background.
S10.4.2 The weight value for load carrying capacity on the RV load carrying capacity labels (Figures 1 and 2) must be displayed to the nearest kilogram with conversion to the nearest pound and must be such that the vehicle's weight does not exceed its GVWR when loaded with the stated load carrying capacity. The UVW and the GVWR used to determine the RV's load carrying capacity must reflect the weights and design of the motor home or RV trailer as configured for delivery to the dealer/service facility. If applicable, the weight of full propane tanks must be included in the RV's UVW and the weight of on-board potable water must be treated as cargo.
S10.4.3 The RV load carrying capacity labels (Figures 1 and 2) must be:
(a) Permanently affixed and must be visibly located on the interior of the forward-most exterior passenger door on the right side of the vehicle; or
(b) If a permanent RV load carrying capacity label (Figure 1 or 2) is affixed in the location specified at S5.3(b), a temporary version of the RV load carrying capacity label (Figure 1 or 2) may be visibly located on the interior of the forward-most exterior passenger door on the right side of the vehicle.
S10.4.4 Permanent and temporary motor home OCCC labels must contain the following information in accordance with Figure 1:
(a) The statement: “MOTOR HOME OCCUPANT AND CARGO CARRYING CAPACITY” in block letters.
(b) The Vehicle Identification Number (VIN).
(c) The statement “THE COMBINED WEIGHT OF OCCUPANTS AND CARGO SHOULD NEVER EXCEED: XXX kg or XXX lbs” in block letters with appropriate values included.
(d) The statement “Safety belt equipped seating capacity: XXX” with the appropriate value included. This is the total number of safety belt equipped seating positions.
(e) The statement: “CAUTION: A full load of water equals XXX kg or XXX lbs of cargo @ 1 kg/L (8.3 lb/gal) and the tongue weight of a towed trailer counts as cargo” with appropriate values included.
S10.4.5 Permanent and temporary RV trailer CCC labels must contain the following information in accordance with Figure 2:
(a) The statement: “RECREATION VEHICLE TRAILER CARGO CARRYING CAPACITY” in block letters.
(b) The Vehicle Identification Number (VIN).
(c) The statement: “THE WEIGHT OF CARGO SHOULD NEVER EXCEED: XXX kg or XXX lbs” in block letters with appropriate values included.
(d) The statement: “CAUTION: A full load of water equals XXX kg or XXX lbs of cargo @ 1 kg/L (8.3 lb/gal)” with appropriate values included.
S10.5 Weight added to motor homes and RV trailers between final vehicle certification and first retail sale of the vehicle.
S10.5.1 If weight exceeding 45.4 kg (100 pounds) is added to a motor home or RV trailer between final vehicle certification and first retail sale of the vehicle, the load carrying capacity values on the RV load carrying capacity labels (Figures 1 and 2) required by S10.4 must be corrected using one or a combination of the following methods:
(a) Permanently affix the load carrying capacity modification label (Figure 3) which displays the amount the load carrying capacity is reduced to the nearest kilogram with conversion to the nearest pound, within 25 millimeters of the original, permanent RV load carrying capacity label (Figure 1 or 2). The load carrying capacity modification label must be legible, visible, permanent, moisture resistant, presented in the English language, have a minimum print size of 2.4 millimeters (3/32 inches) high and be printed in black print on a yellow background. If the manufacturer selects S10.4.3(b), apply a temporary version of the load carrying capacity modification label (Figure 3) within 25 millimeters of the original, temporary RV load carrying capacity label (Figure 1 or 2) on the interior of the forward-most exterior passenger door on the right side of the vehicle. Both temporary and permanent versions of the load carrying capacity modification label (Figure 3) may be printed without values and values may be legibly applied to the label with a black, fine point, indelible marker. The label must contain the statements “CAUTION—LOAD CARRYING CAPACITY REDUCED” in block letters and “Modifications to this vehicle have reduced the original load carrying capacity by XXX kg or XXX lbs” in accordance with Figure 3 with appropriate values in place of XXX. If two load carrying capacity modification labels are required (one permanent and one temporary), the weight values on each must agree, or
(b) Modify the original permanent RV load carrying capacity label (Figure 1 or 2) with correct load carrying capacity weight values. If the manufacturer selects S10.4.3(b), the temporary RV load carrying capacity label (Figure 1 or 2) must also be modified with correct load carrying capacity weight values. Modification of labels requires a machine printed overlay with printed corrected values or blanks for corrected values that may be entered with a black, fine-point, indelible marker. Crossing out old values and entering corrected values on the original label is not permissible, or
(c) Replace the original, permanent RV load carrying capacity label (Figure 1 or 2) with the same label containing correct load carrying capacity weight values. If the manufacturer selects S10.4.3(b), the temporary RV load carrying capacity label (Figure 1 or 2) must also be replaced with the same label containing correct load carrying capacity weight values.
S10.5.2 Corrected load carrying capacity weight values or the weight amount the load carrying capacity is reduced, must reflect the total weight added between final vehicle certification and first retail sale and must be accurate within one percent of the actual added weight. No re-labeling is required if the weight of the vehicle is reduced between final vehicle certification and the first retail sale.
§ 571.121   Standard No. 121; Air brake systems.
S1. Scope. This standard establishes performance and equipment requirements for braking systems on vehicles equipped with air brake systems.
S2. Purpose. The purpose of this standard is to insure safe braking performance under normal and emergency conditions.
S3. Application. This standard applies to trucks, buses, and trailers equipped with air brake systems. However, it does not apply to:
(a) Any trailer that has a width of more than 102.36 inches with extendable equipment in the fully retracted position and is equipped with two short track axles in a line across the width of the trailer.
(b) Any vehicle equipped with an axle that has a gross axle weight rating (GAWR) of 29,000 pounds or more;
(c) Any truck or bus that has a speed attainable in 2 miles of not more than 33 mph;
(d) Any truck that has a speed attainable in 2 miles of not more than 45 mph, an unloaded vehicle weight that is not less than 95 percent of its gross vehicle weight rating (GVWR), and no capacity to carry occupants other than the driver and operating crew;
(e) Any trailer that has a GVWR of more than 120,000 pounds and whose body conforms to that described in the definition of heavy hauler trailer set forth in S4;
(f) Any trailer that has an unloaded vehicle weight which is not less than 95 percent of its GVWR; and
(g) Any load divider dolly.
S4. Definitions.
Agricultural commodity trailer means a trailer that is designed to transport bulk agricultural commodities in off-road harvesting sites and to a processing plant or storage location, as evidenced by skeletal construction that accommodates harvest containers, a maximum length of 28 feet, and an arrangement of air control lines and reservoirs that minimizes damage in field operations.
Air brake system means a system that uses air as a medium for transmitting pressure or force from the driver control to the service brake, including an air-over-hydraulic brake subsystem, but does not include a system that uses compressed air or vacuum only to assist the driver in applying muscular force to hydraulic or mechanical components.
Air-over-hydraulic brake subsystem means a subsystem of the air brake system that uses compressed air to transmit a force from the driver control to a hydraulic brake system to actuate the service brakes.
Antilock brake system or ABS means a portion of a service brake system that automatically controls the degree of rotational wheel slip during braking by:
(1) Sensing the rate of angular rotation of the wheels;
(2) Transmitting signals regarding the rate of wheel angular rotation to one or more controlling devices which interpret those signals and generate responsive controlling output signals; and
(3) Transmitting those controlling signals to one or more modulators which adjust brake actuating forces in response to those signals.
Auto transporter means a truck and a trailer designed for use in combination to transport motor vehicles, in that the towing vehicle is designed to carry cargo at a location other than the fifth wheel and to load this cargo only by means of the towed vehicle.
Common diaphragm means a single brake chamber diaphragm which is a component of the parking, emergency, and service brake systems.
Container chassis trailer means a semitrailer of skeleton construction limited to a bottom frame, one or more axles, specially built and fitted with locking devices for the transport of intermodal shipping containers, so that when the chassis and container are assembled, the units serve the same function as an over the road trailer.
Directly controlled wheel means a wheel for which the degree of rotational wheel slip is sensed, either at that wheel or on the axle shaft for that wheel and corresponding signals are transmitted to one or more modulators that adjust the brake actuating forces at that wheel. Each modulator may also adjust the brake actuating forces at other wheels that are on the same axle or in the same axle set in response to the same signal or signals.
Effective projected luminous lens area means that area of the projection on a plane perpendicular to the lamp axis of that portion of the light-emitting surface that directs light to the photometric test pattern, and does not include mounting hole bosses, reflex reflector area, beads or rims that may glow or produce small areas of increased intensity as a result of uncontrolled light from small areas ( 1/2 degree radius around the test point).
Full-treadle brake application means a brake application in which the treadle valve pressure in any of the valve's output circuits reaches 85 pounds per square inch (psi) within 0.2 seconds after the application is initiated, or in which maximum treadle travel is achieved within 0.2 seconds after the application is initiated.
Heavy hauler trailer means a trailer which has one or more of the following characteristics, but which is not a container chassis trailer:
(1) Its brake lines are designed to adapt to separation or extension of the vehicle frame; or
(2) Its body consists only of a platform whose primary cargo-carrying surface is not more than 40 inches above the ground in an unloaded condition, except that it may include sides that are designed to be easily removable and a permanent “front end structure” as that term is used in § 393.106 of this title.
Independently controlled wheel means a directly controlled wheel for which the modulator does not adjust the brake actuating forces at any other wheel on the same axle.
Indirectly controlled wheel means a wheel at which the degree of rotational wheel slip is not sensed, but at which the modulator of an antilock braking system adjusts its brake actuating forces in response to signals from one or more sensed wheel(s).
Initial brake temperature means the average temperature of the service brakes on the hottest axle of the vehicle 0.2 mile before any brake application in the case of road tests, or 18 seconds before any brake application in the case of dynamometer testing.
Intermodal shipping container means a reusable, transportable enclosure that is especially designed with integral locking devices for securing the container to the trailer to facilitate the efficient and bulk shipping and transfer of goods by, or between various modes of transport, such as highway, rail, sea and air.
Load divider dolly means a trailer composed of a trailer chassis and one or more axles, with no solid bed, body, or container attached, and which is designed exclusively to support a portion of the load on a trailer or truck excluded from all the requirements of this standard.
Maximum drive-through speed means the highest possible constant speed at which the vehicle can be driven through 200 feet of a 500-foot radius curve arc without leaving the 12-foot lane.
Maximum treadle travel means the distance that the treadle moves from its position when no force is applied to its position when the treadle reaches a full stop.
Peak friction coefficient or PFC means the ratio of the maximum value of braking test wheel longitudinal force to the simultaneous vertical force occurring prior to wheel lockup, as the braking torque is progressively increased.
Pulpwood trailer means a trailer that is designed exclusively for harvesting logs or pulpwood and constructed with a skeletal frame with no means for attachment of a solid bed, body, or container, and with an arrangement of air control lines and reservoirs designed to minimize damage in off-road operations.
Tandem axle means a group or set of two or more axles placed in a close arrangement, one behind the other, with the centerlines of adjacent axles not more than 72 inches apart.
Straddle trailer means a trailer that is designed to transport bulk agricultural commodities from the harvesting location as evidenced by a framework that is driven over the cargo and lifting arms that suspend the cargo for transit.
Wheel lockup means 100 percent wheel slip.
S5. Requirements. Each vehicle shall meet the following requirements under the conditions specified in S6. However, at the option of the manufacturer, the following vehicles may meet the stopping distance requirements specified in Table IIa instead of Table II: Three-axle tractors with a front axle that has a GAWR of 14,600 pounds or less, and with two rear drive axles that have a combined GAWR of 45,000 pounds or less, that are manufactured before August 1, 2011; and all other tractors that are manufactured before August 1, 2013.
S5.1 Required equipment for trucks and buses. Each truck and bus shall have the following equipment:
S5.1.1 Air compressor. An air compressor of sufficient capacity to increase air pressure in the supply and service reservoirs from 85 psi to 100 psi when the engine is operating at the vehicle manufacturer's maximum recommended r.p.m. within a time, in seconds, determined by the quotient (Actual reservoir capacity × 25)/Required reservoir capacity.
S5.1.1.1 Air compressor cut-in pressure. The air compressor governor cut-in pressure for each bus shall be 85 p.s.i. or greater. The air compressor governor cut-in pressure for each truck shall be 100 p.s.i. or greater.
S5.1.2 Reservoirs. One or more service reservoir systems, from which air is delivered to the brake chambers, and either an automatic condensate drain valve for each service reservoir or a supply reservoir between the service reservoir system and the source of air pressure.
S5.1.2.1 The combined volume of all service reservoirs and supply reservoirs shall be at least 12 times the combined volume of all service brake chambers. For each brake chamber type having a full stroke at least as great as the first number in Column 1 of Table V, but no more than the second number in Column 1 of Table V, the volume of each brake chamber for purposes of calculating the required combined service and supply reservoir volume shall be either that specified in Column 2 of Table V or the actual volume of the brake chamber at maximum travel of the brake piston or pushrod, whichever is lower. The volume of a brake chamber not listed in Table V is the volume of the brake chamber at maximum travel of the brake piston or pushrod. The reservoirs of the truck portion of an auto transporter need not meet this requirement for reservoir volume.
S5.1.2.2 Each reservoir shall be capable of withstanding an internal hydrostatic pressure of five times the compressor cutout pressure or 500 psi, whichever is greater, for 10 minutes.
S5.1.2.3 Each service reservoir system shall be protected against loss of air pressure due to failure or leakage in the system between the service reservoir and the source of air pressure, by check valves or equivalent devices whose proper functioning can be checked without disconnecting any air line or fitting.
S5.1.2.4 Each reservoir shall have a condensate drain valve that can be manually operated.
S5.1.3 Towing vehicle protection system. If the vehicle is intended to tow another vehicle equipped with air brakes, a system to protect the air pressure in the towing vehicle from the effects of a loss of air pressure in the towed vehicle.
S5.1.4 Pressure gauge. A pressure gauge in each service brake system, readily visible to a person seated in the normal driving position, that indicates the service reservoir system air pressure. The accuracy of the gauge shall be within plus or minus 7 percent of the compressor cut-out pressure.
S5.1.5 Warning signal. A signal, other than a pressure gauge, that gives a continuous warning to a person in the normal driving position when the ignition is in the “on” (“run”) position and the air pressure in the service reservoir system is below 60 psi. The signal shall be either visible within the driver's forward field of view, or both audible and visible.
S5.1.6 Antilock brake system.
S5.1.6.1(a) Each single-unit vehicle manufactured on or after March 1, 1998, shall be equipped with an antilock brake system that directly controls the wheels of at least one front axle and the wheels of at least one rear axle of the vehicle. Wheels on other axles of the vehicle may be indirectly controlled by the antilock brake system.
(b) Each truck tractor manufactured on or after March 1, 1997, shall be equipped with an antilock brake system that directly controls the wheels of at least one front axle and the wheels of at least one rear axle of the vehicle, with the wheels of at least one axle being independently controlled. Wheels on other axles of the vehicle may be indirectly controlled by the antilock brake system. A truck tractor shall have no more than three wheels controlled by one modulator.
S5.1.6.2 Antilock malfunction signal and circuit.
(a) Each truck tractor manufactured on or after March 1, 1997, and each single unit vehicle manufactured on or after March 1, 1998, shall be equipped with an indicator lamp, mounted in front of and in clear view of the driver, which is activated whenever there is a malfunction that affects the generation or transmission of response or control signals in the vehicle's antilock brake system. The indicator lamp shall remain activated as long as such a malfunction exists, whenever the ignition (start) switch is in the “on” (“run”) position, whether or not the engine is running. Each message about the existence of such a malfunction shall be stored in the antilock brake system after the ignition switch is turned to the “off” position and automatically reactivated when the ignition switch is again turned to the “on” (“run”) position. The indicator lamp shall also be activated as a check of lamp function whenever the ignition is turned to the “on” (“run”) position. The indicator lamp shall be deactivated at the end of the check of lamp function unless there is a malfunction or a message about a malfunction that existed when the key switch was last turned to the “off” position.
(b) Each truck tractor manufactured on or after March 1, 2001, and each single unit vehicle manufactured on or after March 1, 2001, that is equipped to tow another air-braked vehicle, shall be equipped with an electrical circuit that is capable of transmitting a malfunction signal from the antilock brake system(s) on one or more towed vehicle(s) (e.g., trailer(s) and dolly(ies)) to the trailer ABS malfunction lamp in the cab of the towing vehicle, and shall have the means for connection of this electrical circuit to the towed vehicle. Each such truck tractor and single unit vehicle shall also be equipped with an indicator lamp, separate from the lamp required in S5.1.6.2(a), mounted in front of and in clear view of the driver, which is activated whenever the malfunction signal circuit described above receives a signal indicating an ABS malfunction on one or more towed vehicle(s). The indicator lamp shall remain activated as long as an ABS malfunction signal from one or more towed vehicle(s) is present, whenever the ignition (start) switch is in the “on” (“run”) position, whether or not the engine is running. The indicator lamp shall also be activated as a check of lamp function whenever the ignition is turned to the “on” (“run”) position. The indicator lamp shall be deactivated at the end of the check of lamp function unless a trailer ABS malfunction signal is present.
(c) [Reserved]
S5.1.6.3 Antilock power circuit for towed vehicles. Each truck tractor manufactured on or after March 1, 1997, and each single unit vehicle manufactured on or after March 1, 1998, that is equipped to tow another air-braked vehicle shall be equipped with one or more electrical circuits that provide continuous power to the antilock system on the towed vehicle or vehicles whenever the ignition (start) switch is in the “on” (“run”) position. Such a circuit shall be adequate to enable the antilock system on each towed vehicle to be fully operable.
S5.1.7 Service brake stop lamp switch. A switch that lights the stop lamps when the service brake control is statically depressed to a point that produces a pressure of 6 psi or less in the service brake chambers.
S5.1.8 Brake distribution and automatic adjustment. Each vehicle shall be equipped with a service brake system acting on all wheels.
(a) Brake adjuster. Wear of the service brakes shall be compensated for by means of a system of automatic adjustment. When inspected pursuant to S5.9, the adjustment of the service brakes shall be within the limits recommended by the vehicle manufacturer.
(b) Brake indicator. For each brake equipped with an external automatic adjustment mechanism and having an exposed pushrod, the condition of service brake under-adjustment shall be displayed by a brake adjustment indicator that is discernible when viewed with 20/40 vision from a location adjacent to or underneath the vehicle, when inspected pursuant to S5.9.
S5.2 Required equipment for trailers. Each trailer shall have the following equipment:
S5.2.1 Reservoirs. One or more reservoirs to which the air is delivered from the towing vehicle.
S5.2.1.1 The total volume of each service reservoir shall be at least eight times the combined volume of all service brake chambers serviced by that reservoir. For each brake chamber type having a full stroke at least as great as the first number in Column 1 of Table V, but no more than the second number in column 1, the volume of each brake chamber for purposes of calculating the required total service reservoir volume shall be either the number specified in Column 2 of Table V or the actual volume of the brake chamber at maximum travel of the brake piston or pushrod, whichever is lower. The volume of a brake chamber not listed in Table V is the volume of the brake chamber at maximum travel of the brake piston or pushrod. The reservoirs on a heavy hauler trailer and the trailer portion of an auto transporter need not meet this requirement for reservoir volume.
S5.2.1.2 Each reservoir shall be capable of withstanding an internal hydrostatic pressure of 500 psi for 10 minutes.
S5.2.1.3 Each reservoir shall have a condensate drain valve that can be manually operated.
S5.2.1.4 Each service reservoir shall be protected against loss of air pressure due to failure or leakage in the system between the service reservoir and its source of air pressure by check valves or equivalent devices.
S5.2.2 Brake distribution and automatic adjustment. Each vehicle shall be equipped with a service brake system acting on all wheels.
(a) Brake adjuster. Wear of the service brakes shall be compensated for by means of a system of automatic adjustment. When inspected pursuant to S5.9, the adjustment of the service brakes shall be within the limits recommended by the vehicle manufacturer.
(b) Brake indicator. For each brake equipped with an external automatic adjustment mechanism and having an exposed pushrod, the condition of service brake under-adjustment shall be displayed by a brake adjustment indicator in a manner that is discernible when viewed with 20/40 vision from a location adjacent to or underneath the vehicle, when inspected pursuant to S5.9.
S5.2.3 Antilock brake system.
S5.2.3.1(a) Each semitrailer (including a trailer converter dolly) manufactured on or after March 1, 1998, shall be equipped with an antilock brake system that directly controls the wheels of at least one axle of the vehicle. Wheels on other axles of the vehicle may be indirectly controlled by the antilock brake system.
(b) Each full trailer manufactured on or after March 1, 1998, shall be equipped with an antilock brake system that directly controls the wheels of at least one front axle of the vehicle and at least one rear axle of the vehicle. Wheels on other axles of the vehicle may be indirectly controlled by the antilock brake system.
S5.2.3.2 Antilock malfunction signal. Each trailer (including a trailer converter dolly) manufactured on or after March 1, 2001, that is equipped with an antilock brake system shall be equipped with an electrical circuit that is capable of signaling a malfunction in the trailer's antilock brake system, and shall have the means for connection of this antilock brake system malfunction signal circuit to the towing vehicle. The electrical circuit need not be separate or dedicated exclusively to this malfunction signaling function. The signal shall be present whenever there is a malfunction that affects the generation or transmission of response or control signals in the trailer's antilock brake system. The signal shall remain present as long as the malfunction exists, whenever power is supplied to the antilock brake system. Each message about the existence of such a malfunction shall be stored in the antilock brake system whenever power is no longer supplied to the system, and the malfunction signal shall be automatically reactivated whenever power is again supplied to the trailer's antilock brake system. In addition, each trailer manufactured on or after March 1, 2001, that is designed to tow other air-brake equipped trailers shall be capable of transmitting a malfunction signal from the antilock brake systems of additional trailers it tows to the vehicle towing it.
S5.2.3.3 Antilock malfunction indicator.
(a) In addition to the requirements of S5.2.3.2, each trailer and trailer converter dolly shall be equipped with an external antilock malfunction indicator lamp that meets the requirements of S5.2.3.3 (b) through (d).
(b)(1) The lamp shall be designed to conform to the performance requirements of SAE Recommended Practice J592 JUN92 (incorporated by reference, see § 571.5), or SAE Recommended Practice J592e (1972) (incorporated by reference, see § 571.5), for combination, clearance, and side marker lamps, which are marked with a “PC” or “P2” on the lens or housing, in accordance with SAE Recommended Practice J759 JAN95 (incorporated by reference, see § 571.5).
(2) The color of the lamp shall be yellow.
(3) The letters “ABS” shall be permanently molded, stamped, or otherwise marked or labeled in letters not less than 10 mm (0.4 inches) high on the lamp lens or its housing to identify the function of the lamp. Alternatively, the letters “ABS” may be painted on the trailer body or dolly or a plaque with the letters “ABS” may be affixed to the trailer body or converter dolly; the letters “ABS” shall be not less than 25 mm (1 inch) high. A portion of one of the letters in the alternative identification shall be not more than 150 mm (5.9 inches) from the edge of the lamp lens.
(c) Location requirements. (1) Each trailer that is not a trailer converter dolly shall be equipped with a lamp mounted on a permanent structure on the left side of the trailer as viewed from the rear, no closer than 150 mm (5.9 inches), and no farther than 600 mm (23.6 inches) from the red rear side marker lamp, when measured between the closest edge of the effective projected luminous lens area of each lamp.
(2) Each trailer converter dolly shall be equipped with a lamp mounted on a permanent structure of the dolly so that the lamp is not less than 375 mm (14.8 inches) above the road surface when measured from the center of the lamp with the dolly at curb weight. When a person, standing 3 meters (9.8 feet) from the lamp, views the lamp from a perspective perpendicular to the vehicle's centerline, no portion of the lamp shall be obscured by any structure on the dolly.
(3) Each trailer that is not a trailer converter dolly and on which the malfunction indicator lamp cannot be placed within the location specified in S5.2.3.3(c)(1) shall be equipped with a lamp mounted on a permanent structure on the left side of the trailer as viewed from the rear, near the red rear side marker lamp or on the front face of the left rear fender of a trailer equipped with fenders.
(d) The lamp shall be illuminated whenever power is supplied to the antilock brake system and there is a malfunction that affects the generation or transmission of response or control signals in the trailer's antilock brake system. The lamp shall remain illuminated as long as such a malfunction exists and power is supplied to the antilock brake system. Each message about the existence of such a malfunction shall be stored in the antilock brake system whenever power is no longer supplied to the system. The lamp shall be automatically reactivated when power is again supplied to the trailer's antilock brake system. The lamp shall also be activated as a check of lamp function whenever power is first supplied to the antilock brake system and the vehicle is stationary. The lamp shall be deactivated at the end of the check of lamp function, unless there is a malfunction or a message about a malfunction that existed when power was last supplied to the antilock brake system.
S5.3 Service brakes—road tests. The service brake system on each truck tractor shall, under the conditions of S6, meet the requirements of S5.3.1, S5.3.3, S5.3.4, and S5.3.6, when tested without adjustments other than those specified in this standard. The service brake system on each bus and truck (other than a truck tractor shall) manufactured before July 1, 2005 and each bus and truck (other than a truck tractor) manufactured in two or more stages shall, under the conditions of S6, meet the requirements of S5.3.1, S5.3.3, and S5.3.4 when tested without adjustments other than those specified in this standard. The service brake system on each bus and truck (other than a truck tractor) manufactured on or after July 1, 2005 and each bus and truck (other than a truck tractor) manufactured in two or more stages on or after July 1, 2006 shall, under the conditions of S6, meet the requirements of S5.3.1, S5.3.3, S5.3.4, and S5.3.6, when tested without adjustments other than those specified in this standard. The service brake system on each trailer shall, under the conditions of S6, meet the requirements of S5.3.3, S5.3.4, and S5.3.5 when tested without adjustments other than those specified in this standard. However, a heavy hauler trailer and the truck and trailer portions of an auto transporter need not met the requirements of S5.3.
S5.3.1 Stopping distance—trucks and buses. When stopped six times for each combination of vehicle type, weight, and speed specified in S5.3.1.1, in the sequence specified in Table I, each truck tractor manufactured on or after March 1, 1997, and each single unit vehicle manufactured on or after March 1, 1998, shall stop at least once in not more than the distance specified in Table II, measured from the point at which movement of the service brake control begins, without any part of the vehicle leaving the roadway, and with wheel lockup permitted only as follows:
(a) At vehicle speeds above 20 mph, any wheel on a nonsteerable axle other than the two rearmost nonliftable, nonsteerable axles may lock up, for any duration. The wheels on the two rearmost nonliftable, nonsteerable axles may lock up according to S5.3.1(b).
(b) At vehicle speeds above 20 mph, one wheel on any axle or two wheels on any tandem may lock up for any duration.
(c) At vehicle speeds above 20 mph, any wheel not permitted to lock in S5.3.1 (a) or (b) may lock up repeatedly, with each lockup occurring for a duration of one second or less.
(d) At vehicle speeds of 20 mph or less, any wheel may lock up for any duration.
S5.3.1.1 Stop the vehicle from 60 mph on a surface with a peak friction coefficient of 1.02 with the vehicle loaded as follows:
(a) Loaded to its GVWR so that the load on each axle, measured at the tire-ground interface, is most nearly proportional to the axles' respective GAWRs, without exceeding the GAWR of any axle.
(b) In the truck tractor only configuration plus up to 500 lbs. or, at the manufacturer's option, at its unloaded weight plus up to 500 lbs. (including driver and instrumentation) and plus not more than an additional 1,000 lbs. for a roll bar structure on the vehicle, and
(c) At its unloaded vehicle weight (except for truck tractors) plus up to 500 lbs. (including driver and instrumentation) or, at the manufacturer's option, at its unloaded weight plus up to 500 lbs. (including driver and instrumentation) plus not more than an additional 1,000 lbs. for a roll bar structure on the vehicle. If the speed attainable in two miles is less than 60 mph, the vehicle shall stop from a speed in Table II that is four to eight mph less than the speed attainable in two miles.
S5.3.2 [Reserved]
S5.3.3 Brake actuation time. Each service brake system shall meet the requirements of S5.3.3.1 (a) and (b).
S5.3.3.1(a) With an initial service reservoir system air pressure of 100 psi, the air pressure in each brake chamber shall, when measured from the first movement of the service brake control, reach 60 psi in not more than 0.45 second in the case of trucks and buses, 0.50 second in the case of trailers, other than trailer converter dollies, designed to tow another vehicle equipped with air brakes, 0.55 second in the case of trailer converter dollies, and 0.60 second in the case of trailers other than trailers designed to tow another vehicle equipped with air brakes. A vehicle designed to tow another vehicle equipped with air brakes shall meet the above actuation time requirement with a 50-cubic-inch test reservoir connected to the control line output coupling. A trailer, including a trailer converter dolly, shall meet the above actuation time requirement with its control line input coupling connected to the test rig shown in Figure 1.
(b) For a vehicle that is designed to tow another vehicle equipped with air brakes, the pressure in the 50-cubic-inch test reservoir referred to in S5.3.3.1(a) shall, when measured from the first movement of the service brake control, reach 60 psi not later than the time the fastest brake chamber on the vehicle reaches 60 psi or, at the option of the manufacturer, in not more than 0.35 second in the case of trucks and buses, 0.55 second in the case of trailer converter dollies, and 0.50 second in the case of trailers other than trailer converter dollies.
S5.3.4 Brake release time. Each service brake system shall meet the requirements of S5.3.4.1 (a) and (b).
S5.3.4.1(a) With an initial service brake chamber air pressure of 95 psi, the air pressure in each brake chamber shall, when measured from the first movement of the service brake control, fall to 5 psi in not more than 0.55 second in the case of trucks and buses; 1.00 second in the case of trailers, other than trailer converter dollies, designed to tow another vehicle equipped with air brakes; 1.10 seconds in the case of trailer converter dollies; and 1.20 seconds in the case of trailers other than trailers designed to tow another vehicle equipped with air brakes. A vehicle designated to tow another vehicle equipped with air brakes shall meet the above release time requirement with a 50-cubic-inch test reservoir connected to the control line output coupling. A trailer, including a trailer converter dolly, shall meet the above release time requirement with its control line input coupling connected to the test rig shown in Figure 1.
(b) For vehicles designed to tow another vehicle equipped with air brakes, the pressure in the 50-cubic-inch test reservoir referred to in S5.3.4.1(a) shall, when measured from the first movement of the service brake control, fall to 5 psi in not more than 0.75 seconds in the case of trucks and buses, 1.10 seconds in the case of trailer converter dollies, and 1.00 seconds in the case of trailers other than trailer converter dollies.
S5.3.5 Control signal pressure differential—converter dollies and trailers designed to tow another vehicle equipped with air brakes.
(a) For a trailer designed to tow another vehicle equipped with air brakes, the pressure differential between the control line input coupling and a 50-cubic-inch test reservoir attached to the control line output coupling shall not exceed the values specified in S5.3.5(a) (1), (2), and (3) under the conditions specified in S5.3.5(b) (1) through (4):
(1) 1 psi at all input pressures equal to or greater than 5 psi, but not greater than 20 psi;
(2) 2 psi at all input pressures equal to or greater than 20 psi but not greater than 40 psi; and
(3) Not more than a 5-percent differential at any input pressure equal to or greater than 40 psi.
(b) The requirements in S5.3.5(a) shall be met—
(1) When the pressure at the input coupling is steady, increasing or decreasing;
(2) When air is applied to or released from the control line input coupling using the trailer test rig shown in Figure 1;
(3) With a fixed orifice consisting of a 0.0180 inch diameter hole (no. 77 drill bit) in a 0.032 inch thick disc installed in the control line between the trailer test rig coupling and the vehicle's control line input coupling; and
(4) Operating the trailer test rig in the same manner and under the same conditions as it is operated during testing to measure brake actuation and release times, as specified in S5.3.3 and S5.3.4, except for the installation of the orifice in the control line to restrict airflow rate.
S5.3.6 Stability and control during braking—trucks and buses. When stopped four consecutive times for each combination of weight, speed, and road conditions specified in S5.3.6.1 and S5.3.6.2, each truck tractor shall stop at least three times within the 12-foot lane, without any part of the vehicle leaving the roadway. When stopped four consecutive times for each combination of weight, speed, and road conditions specified in S5.3.6.1 and S5.3.6.2, each bus and truck (other than a truck tractor) manufactured on or after July 1, 2005, and each bus and truck (other than a truck tractor) manufactured in two or more stages on or after July 1, 2006, shall stop at least three times within the 12-foot lane, without any part of the vehicle leaving the roadway.
S5.3.6.1 Using a full-treadle brake application for the duration of the stop, stop the vehicle from 30 mph or 75 percent of the maximum drive-through speed, whichever is less, on a 500-foot radius curved roadway with a wet level surface having a peak friction coefficient of 0.55 when measured on a straight or curved section of the curved roadway using an ASTM F2493 standard reference tire, in accordance with ASTM E1337-19 (incorporated by reference, see § 571.5), at a speed of 40 mph, with water delivery.
S5.3.6.2 Stop the vehicle, with the vehicle:
(a) Loaded to its GVWR, for a truck tractor, and
(b) At its unloaded weight plus up to 500 pounds (including driver and instrumentation), or at the manufacturer's option, at its unloaded weight plus up to 500 pounds (including driver and instrumentation) and plus not more than an additional 1000 pounds for a roll bar structure on the vehicle, for a truck, bus, or truck tractor.
S5.4 Service brake system—dynamometer tests. When tested without prior road testing, under the conditions of S6.2, each brake assembly shall meet the requirements of S5.4.1, S5.4.2, and S5.4.3 when tested in sequence and without adjustments other than those specified in the standard. For purposes of the requirements of S5.4.2 and S5.4.3, an average deceleration rate is the change in velocity divided by the deceleration time measured from the onset of deceleration.
S5.4.1 Brake retardation force. The sum of the retardation forces exerted by the brakes on each vehicle designed to be towed by another vehicle equipped with air brakes shall be such that the quotient sum of the brake retardation forces / sum of GAWR's relative to brake chamber air pressure, and shall have values not less than those shown in Column 1 of Table III. Retardation force shall be determined as follows:
S5.4.1.1 After burnishing the brake pursuant to S6.2.6, retain the brake assembly on the inertia dynamometer. With an initial brake temperature between 125 °F. and 200 °F., conduct a stop from 50 m.p.h., maintaining brake chamber air pressure at a constant 20 psi. Measure the average torque exerted by the brake from the time the specified air pressure is reached until the brake stops and divide by the static loaded tire radius specified by the tire manufacturer to determine the retardation force. Repeat the procedure six times, increasing the brake chamber air pressure by 10 psi each time. After each stop, rotate the brake drum or disc until the temperature of the brake falls to between 125 °F. and 200 °F.
S5.4.2 Brake power. When mounted on an inertia dynamometer, each brake shall be capable of making 10 consecutive decelerations at an average rate of 9 f.p.s.p.s. from 50 m.p.h. to 15 m.p.h., at equal intervals of 72 seconds, and shall be capable of decelerating to a stop from 20 m.p.h. at an average deceleration rate of 14 f.p.s.p.s. 1 minute after the 10th deceleration. The series of decelerations shall be conducted as follows:
S5.4.2.1 With an initial brake temperature between 150 °F. and 200 °F. for the first brake application, and the drum or disc rotating at a speed equivalent to 50 m.p.h., apply the brake and decelerate at an average deceleration rate of 9 f.p.s.p.s. to 15 m.p.h. Upon reaching 15 m.p.h., accelerate to 50 m.p.h. and apply the brake for a second time 72 seconds after the start of the first application. Repeat the cycle until 10 decelerations have been made. The service line air pressure shall not exceed 100 psi during any deceleration.
S5.4.2.2 One minute after the end of the last deceleration required by S5.4.2.1 and with the drum or disc rotating at a speed of 20 m.p.h., decelerate to a stop at an average deceleration rate of 14 f.p.s.p.s.
S5.4.3 Brake recovery. Except as provided in S5.4.3(a) and (b), starting two minutes after completing the tests required by S5.4.2, a vehicle's brake shall be capable of making 20 consecutive stops from 30 mph at an average deceleration rate of 12 f.p.s.p.s., at equal intervals of one minute measured from the start of each brake application. The service line air pressure needed to attain a rate of 12 f.p.s.p.s. shall be not more than 85 lb/in 2 , and not less than 20lb/in 2 for a brake not subject to the control of an antilock system, or 12 lb/in 2 for a brake subject to the control of an antilock system.
(a) Notwithstanding S5.4.3, neither front axle brake of a truck-tractor is subject to the requirements set forth in S5.4.3.
(b) Notwithstanding S5.4.3, neither front axle brake of a bus or a truck other than a truck-tractor is subject to the requirement set forth in S5.4.3 prohibiting the service line air pressure from being less than 20 lb/in 2 for a brake not subject to the control of an antilock system or 12 lb/in 2 for a brake subject to the control of an antilock system.
S5.5 Antilock system.
S5.5.1 Antilock system malfunction. On a truck tractor manufactured on or after March 1, 1997, that is equipped with an antilock brake system and a single unit vehicle manufactured on or after March 1, 1998, that is equipped with an antilock brake system, a malfunction that affects the generation or transmission of response or control signals of any part of the antilock system shall not increase the actuation and release times of the service brakes.
S5.5.2 Antilock system power—trailers. On a trailer (including a trailer converter dolly) manufactured on or after March 1, 1998, that is equipped with an antilock system that requires electrical power for operation, the power shall be obtained from the towing vehicle through one or more electrical circuits which provide continuous power whenever the powered vehicle's ignition (start) switch is in the “on” (“run”) position. The antilock system shall automatically receive power from the stoplamp circuit, if the primary circuit or circuits are not functioning. Each trailer (including a trailer converter dolly) manufactured on or after March 1, 1998, that is equipped to tow another air-braked vehicle shall be equipped with one or more circuits which provide continuous power to the antilock system on the vehicle(s) it tows. Such circuits shall be adequate to enable the antilock system on each towed vehicle to be fully operable.
S5.6 Parking brakes.
(a) Except as provided in S5.6(b) and S5.6(c), each vehicle other than a trailer converter dolly shall have a parking brake system that under the conditions of S6.1 meets the requirements of:
(1) S5.6.1 or S5.6.2, at the manufacturer's option, and
(2) S5.6.3, S5.6.4, S5.6.5, and S5.6.6.
(b) At the option of the manufacturer, for vehicles equipped with brake systems which incorporate a common diaphragm, the performance requirements specified in S5.6(a) which must be met with any single leakage-type failure in a common diaphragm may instead be met with the level of leakage-type failure determined in S5.6.7. The election of this option does not affect the performance requirements specified in S5.6(a) which apply with single leakage-type failures other than failures in a common diaphragm.
(c) At the option of the manufacturer, the trailer portion of any agricultural commodity trailer, heavy hauler trailer, or pulpwood trailer may meet the requirements of § 393.43 of this title instead of the requirements of S5.6(a).
S5.6.1 Static retardation force. With all other brakes made inoperative, during a static drawbar pull in a forward or rearward direction, the static retardation force produced by the application of the parking brakes shall be:
(a) In the case of a vehicle other than a truck-tractor that is equipped with more than two axles, such that the quotient static retardation force/GAWR is not less than 0.28 for any axle other than a steerable front axle; and
(b) In the case of a truck-tractor that is equipped with more than two axles, such that the quotient static retardation force/GVWR is not less than 0.14.
S5.6.2 Grade holding. With all parking brakes applied, the vehicle shall remain stationary facing uphill and facing downhill on a smooth, dry portland cement concrete roadway with a 20-percent grade, both
(a) When loaded to its GVWR, and
(b) At its unloaded vehicle weight plus 1500 pounds (including driver and instrumentation and roll bar).
S5.6.3 Application and holding. Each parking brake system shall meet the requirements of S5.6.3.1 through S5.6.3.4.
S5.6.3.1 The parking brake system shall be capable of achieving the minimum performance specified either in S5.6.1 or S5.6.2 with any single leakage-type failure, in any other brake system, of a part designed to contain compressed air or brake fluid (excluding failure of a component of a brake chamber housing but including failure of any brake chamber diaphragm that is part of any other brake system including a diaphragm which is common to the parking brake system and any other brake system), when the pressures in the vehicle's parking brake chambers are at the levels determined in S5.6.3.4.
S5.6.3.2 A mechanical means shall be provided that, after a parking brake application is made with the pressures in the vehicle's parking brake chambers at the levels determined in S5.6.3.4, and all air and fluid pressures in the vehicle's braking systems are then bled down to zero, and without using electrical power, holds the parking brake application with sufficient parking retardation force to meet the minimum performance specified in S5.6.3.1 and in either S5.6.1 or S5.6.2.
S5.6.3.3 For trucks and buses, with an initial reservoir system pressure of 100 psi and, if designed to tow a vehicle equipped with air brakes, with a 50 cubic inch test reservoir connected to the supply line coupling, no later than three seconds from the time of actuation of the parking brake control, the mechanical means referred to in S5.6.3.2 shall be actuated. For trailers, with the supply line initially pressurized to 100 psi using the supply line portion of the trailer test rig (Figure 1) and, if designed to tow a vehicle equipped with air brakes, with a 50 cubic inch test reservoir connected to the rear supply line coupling, no later than three seconds from the time venting to the atmosphere of the front supply line coupling is initiated, the mechanical means referred to in S5.6.3.2 shall be actuated. This requirement shall be met for trucks, buses and trailers both with and without any single leakage-type failure, in any other brake system, of a part designed to contain compressed air or brake fluid (consistent with the parenthetical phrase specified in S5.6.3.1).
S5.6.3.4 The parking brake chamber pressures for S5.6.3.1 and S5.6.3.2 are determined as follows. For trucks and buses, with an initial reservoir system pressure of 100 psi and, if designed to tow a vehicle equipped with air brakes, with a 50 cubic inch test reservoir connected to the supply line coupling, any single leakage type failure, in any other brake system, of a part designed to contain compressed air or brake fluid (consistent with the parenthetical phrase specified in S5.6.3.1), is introduced in the brake system. The parking brake control is actuated and the pressures in the vehicle's parking brake chambers are measured three seconds after that actuation is initiated. For trailers, with the supply line initially pressurized to 100 psi using the supply line portion of the trailer test rig (Figure 1) and, if designed to tow a vehicle equipped with air brakes, with a 50 cubic inch test reservoir connected to the rear supply line coupling, any single leakage type failure, in any other brake system, of a part designed to contain compressed air or brake fluid (consistent with the parenthetical phrase specified in S5.6.3.1), is introduced in the brake system. The front supply line coupling is vented to the atmosphere and the pressures in the vehicle's parking brake chambers are measured three seconds after that venting is initiated.
S5.6.4 Parking brake control—trucks and buses. The parking brake control shall be separate from the service brake control. It shall be operable by a person seated in the normal driving position. The control shall be identified in a manner that specifies the method of control operation. The parking brake control shall control the parking brakes of the vehicle and of any air braked vehicle that it is designed to tow.
S5.6.5 Release Performance. Each parking brake system shall meet the requirements specified in S5.6.5.1 through S5.6.5.4.
S5.6.5.1 For trucks and buses, with initial conditions as specified in S5.6.5.2, at all times after an application actuation of the parking brake control, and with any subsequent level of pressure, or combination of levels of pressure, in the reservoirs of any of the vehicle's brake systems, no reduction in parking brake retardation force shall result from a release actuation of the parking brake control unless the parking brakes are capable, after such release, of being reapplied at a level meeting the minimum performance specified either in S5.6.1 or S5.6.2. This requirement shall be met both with and without the engine on, and with and without single leakage-type failure, in any other brake system, of a part designed to contain compressed air or brake fluid (consistent with the parenthetical phrase specified in S5.6.3.1).
S5.6.5.2 The initial conditions for S5.6.5.1 are as follows: The reservoir system pressure is 100 psi. If the vehicle is designed to tow a vehicle equipped with air brakes, a 50 cubic inch test reservoir is connected to the supply line coupling.
S5.6.5.3 For trailers, with initial conditions as specified in S5.6.5.4, at all times after actuation of the parking brakes by venting the front supply line coupling to the atmosphere, and with any subsequent level of pressure, or combination of levels of pressure, in the reservoirs of any of the vehicle's brake systems, the parking brakes shall not be releasable by repressurizing the supply line using the supply line portion of the trailer test rig (Figure 1) to any pressure above 70 psi, unless the parking brakes are capable, after such release, of reapplication by subsequent venting of the front supply line coupling to the atmosphere, at a level meeting the minimum performance specified either in S5.6.1 or S5.6.2. This requirement shall be met both with and without any single leakage-type failure, in any other brake system, of a part designed to contain compressed air or brake fluid (consistent with the parenthetical phrase specified in S5.6.3.1).
S5.6.5.4 The initial conditions for S5.6.5.3 are as follows: The reservoir system and supply line are pressurized to 100 psi, using the supply line portion of the trailer test rig (Figure 1). If the vehicle is designed to tow a vehicle equipped with air brakes, a 50 cubic inch test reservoir is connected to the rear supply line coupling.
S5.6.6 Accumulation of actuation energy. Each parking brake system shall meet the requirements specified in S5.6.6.1 through S5.6.6.6.
S5.6.6.1 For trucks and buses, with initial conditions as specified in S5.6.6.2, the parking brake system shall be capable of meeting the minimum performance specified either in S5.6.1 or S5.6.2, with any single leakage-type failure, in any other brake system, of a part designed to contain compressed air or brake fluid (consistent with the parenthetical phrase specified in S5.6.3.1) at the conclusion of the test sequence specified in S5.6.6.3.
S5.6.6.2 The initial conditions for S5.6.6.1 are as follows: The engine is on. The reservoir system pressure is 100 psi. If the vehicle is designed to tow a vehicle equipped with air brakes, a 50 cubic inch test reservoir is connected to the supply line coupling.
S5.6.6.3 The test sequence for S5.6.6.1 is as follows: The engine is turned off. Any single leakage type failure, in any other brake system, of a part designed to contain compressed air or brake fluid (consistent with the parenthetical phrase specified in S5.6.3.1), is then introduced in the brake system. An application actuation of the parking brake control is then made. Thirty seconds after such actuation, a release actuation of the parking brake control is made. Thirty seconds after the release actuation, a final application actuation of the parking brake control is made.
S5.6.6.4 For trailers, with initial conditions as specified in S5.6.6.5, the parking brake system shall be capable of meeting the minimum performance specified either in S5.6.1 or S5.6.2, with any single leakage-type failure, in any other brake system, of a part designed to contain compressed air or brake fluid (consistent with the parenthetical phrase specified in S5.6.3.1), at the conclusion of the test sequence specified in S5.6.6.6.
S5.6.6.5 The initial conditions for S5.6.6.4 are as follows: The reservoir system and supply line are pressurized to 100 psi, using the supply line portion of the trailer test rig (Figure 1). If the vehicle is designed to tow a vehicle equipped with air brakes, a 50 cubic inch test reservoir is connected to the rear supply line coupling.
S5.6.6.6 The test sequence for S5.6.6.4 is as follows. Any single leakage type failure, in any other brake system, of a part designed to contain compressed air or brake fluid (consistent with the parenthetical phrase specified in S5.6.3.1), is introduced in the brake system. The front supply line coupling is vented to the atmosphere. Thirty seconds after the initiation of such venting, the supply line is repressurized with the trailer test rig (Figure 1). Thirty seconds after the initiation of such repressurizing of the supply line, the front supply line is vented to the atmosphere. This procedure is conducted either by connection and disconnection of the supply line coupling or by use of a valve installed in the supply line portion of the trailer test rig near the supply line coupling.
S5.6.7 Maximum level of common diaphragm leakage-type failure/ Equivalent level of leakage from the air chamber containing that diaphragm. In the case of vehicles for which the option in S5.6(b) has been elected, determine the maximum level of common diaphragm leakage-type failure (or equivalent level of leakage from the air chamber containing that diaphragm) according to the procedures set forth in S5.6.7.1 through S5.6.7.2.3.
S5.6.7.1 Trucks and buses.
S5.6.7.1.1 According to the following procedure, determine the threshold level of common diaphragm leakage-type failure (or equivalent level of leakage from the air chamber containing that diaphragm) at which the vehicle's parking brakes become unreleasable. With an initial reservoir system pressure of 100 psi, the engine turned off, no application of any of the vehicle's brakes, and, if the vehicle is designed to tow a vehicle equipped with air brakes, a 50 cubic inch test reservoir connected to the supply line coupling, introduce a leakage-type failure of the common diaphragm (or equivalent leakage from the air chamber containing that diaphragm). Apply the parking brakes by making an application actuation of the parking brake control. Reduce the pressures in all of the vehicle's reservoirs to zero, turn on the engine and allow it to idle, and allow the pressures in the vehicle's reservoirs to rise until they stabilize or until the compressor shut-off point is reached. At that time, make a release actuation of the parking brake control, and determine whether all of the mechanical means referred to in S5.6.3.2 continue to be actuated and hold the parking brake applications with sufficient parking retardation force to meet the minimum performance specified in either S5.6.1 or S5.6.2. Repeat this procedure with progressively decreasing or increasing levels (whichever is applicable) of leakage-type diaphragm failures or equivalent leakages, to determine the minimum level of common diaphragm leakage-type failure (or equivalent level of leakage from the air chamber containing that diaphragm) at which all of the mechanical means referred to in S5.6.3.2 continue to be actuated and hold the parking brake applications with sufficient parking retardation forces to meet the minimum performance specified in either S5.6.1 or S5.6.2.
S5.6.7.1.2 At the level of common diaphragm leakage-type failure (or equivalent level of leakage from the air chamber containing that diaphragm) determined in S5.6.7.1.1, and using the following procedure, determine the threshold maximum reservoir rate (in psi per minute). With an initial reservoir system pressure of 100 psi, the engine turned off, no application of any of the vehicle's brakes and, if the vehicle is designed to tow a vehicle equipped with air brakes, a 50 cubic inch test reservoir connected to the supply line coupling, make an application actuation of the parking brake control. Determine the maximum reservoir leakage rate (in psi per minute), which is the maximum rate of decrease in air pressure of any of the vehicle's reservoirs that results after that parking brake application.
S5.6.7.1.3 Using the following procedure, introduce a leakage-type failure of the common diaphragm (or equivalent leakage from the air chamber containing that diaphragm) that results in a maximum reservoir leakage rate that is three times the threshold maximum reservoir leakage rate determined in S5.6.7.1.2. With an initial reservoir system pressure of 100 psi, the engine turned off, no application of any of the vehicle's brakes and, if the vehicle is designed to tow a vehicle equipped with air brakes, a 50 cubic inch test reservoir connected to the supply line coupling, make an application actuation of the parking brake control. Determine the maximum reservoir leakage rate (in psi per minute), which is the maximum rate of decrease in air pressure of any of the vehicle's reservoirs that results after that parking brake application. The level of common diaphragm leakage-type failure (or equivalent level of leakage from the air chamber containing that diaphragm) associated with this reservoir leakage rate is the level that is to be used under the option set forth in S5.6(b).
S5.6.7.2 Trailers.
S5.6.7.2.1 According to the following procedure, determine the threshold level of common diaphragm leakage-type failure (or equivalent level of leakage from the air chamber containing that diaphragm) at which the vehicle's parking brakes become unreleasable. With an initial reservoir system and supply line pressure of 100 psi, no application of any of the vehicle's brakes, and, if the vehicle is designed to tow a vehicle equipped with air brakes, a 50 cubic inch test reservoir connected to the supply line coupling, introduce a leakage-type failure of the common diaphragm (or equivalent leakage from the air chamber containing that diaphragm). Make a parking brake application by venting the front supply line coupling to the atmosphere, and reduce the pressures in all of the vehicle's reservoirs to zero. Pressurize the supply line by connecting the trailer's front supply line coupling to the supply line portion of the trailer test rig (Figure 1) with the regulator of the trailer test rig set at 100 psi, and determine whether all of the mechanical means referred to in S5.6.3.2 continue to be actuated and hold the parking brake applications with sufficient parking retardation forces to meet the minimum performance specified in either S5.6.1 or S5.6.2. Repeat this procedure with progressively decreasing or increasing levels (whichever is applicable) of leakage-type diaphragm failures or equivalent leakages, to determine the minimum level of common diaphragm leakage-type failure (or equivalent level of leakage from the air chamber containing that diaphragm) at which all of the mechanical means referred to in S5.6.3.2 continue to be actuated and hold the parking brake applications with sufficient parking retardation forces to meet the minimum performance specified in either S5.6.1 or S5.6.2.
S5.6.7.2.2 At the level of common diaphragm leakage-type failure (or equivalent level of leakage from the air chamber containing that diaphragm) determined in S5.6.7.2.1, and using the following procedure, determine the threshold maximum reservoir leakage rate (in psi per minute). With an initial reservoir system and supply line pressure of 100 psi, no application of any of the vehicle's brakes and, if the vehicle is designed to tow a vehicle equipped with air brakes, a 50 cubic inch test reservoir connected to the rear supply line coupling, make a parking brake application by venting the front supply line coupling to the atmosphere. Determine the maximum reservoir leakage rate (in psi per minute), which is the maximum rate of decrease in air pressure of any of the vehicle's reservoirs that results after that parking brake application.
S5.6.7.2.3 Using the following procedure, a leakage-type failure of the common diaphragm (or equivalent leakage from the air chamber containing that diaphragm) that results in a maximum reservoir leakage rate that is three times the threshold maximum reservoir leakage rate determined in S5.6.7.2.2. With an initial reservoir system and supply line pressure of 100 psi, no application of any of the vehicle's brakes and, if the vehicle is designed to tow a vehicle equipped with air brakes, a 50 cubic inch test reservoir connected to the rear supply line coupling, make a parking brake application by venting the front supply line coupling to the atmosphere. Determine the maximum reservoir leakage rate (in psi per minute), which is the maximum rate of decrease in air pressure of any of the vehicle's reservoirs that results after that parking brake application. The level of common diaphragm leakage-type failure (or equivalent level of leakage from the air chamber containing that diaphragm) associated with this reservoir leakage rate is the level that is to be used under the option set forth in S5.6(b).
S5.7 Emergency brake system for trucks and buses. Each vehicle shall be equipped with an emergency brake system which, under the conditions of S6.1, conforms to the requirements of S5.7.1 through S5.7.3. However, the truck portion of an auto transporter need not meet the road test requirements of S5.7.1 and S5.7.3.
S5.7.1 Emergency brake system performance. When stopped six times for each combination of weight and speed specified in S5.3.1.1, except for a loaded truck tractor with an unbraked control trailer, on a road surface having a PFC of 1.02, with a single failure in the service brake system of a part designed to contain compressed air or brake fluid (except failure of a common valve, manifold, brake fluid housing, or brake chamber housing), the vehicle shall stop at least once in not more than the distance specified in Column 5 of Table II, measured from the point at which movement of the service brake control begins, except that a truck-tractor tested at its unloaded vehicle weight plus up to 1,500 pounds shall stop at least once in not more than the distance specified in Column 6 of Table II. The stop shall be made without any part of the vehicle leaving the roadway, and with unlimited wheel lockup permitted at any speed.
S5.7.2 Emergency brake system operation. The emergency brake system shall be applied and released, and be capable of modulation, by means of the service brake control.
S5.7.3 Towing vehicle emergency brake requirements. In addition to meeting the other requirements of S5.7, a vehicle designed to tow another vehicle equipped with air brakes shall—
(a) In the case of a truck-tractor in the unloaded condition and a single unit truck which is capable of towing an airbrake equipped vehicle and is loaded to GVWR, be capable of meeting the requirements of S5.7.1 by operation of the service brake control only, with the trailer air supply line and air control line from the towing vehicle vented to the atmosphere in accordance with S6.1.14;
(b) Be capable of modulating the air in the supply or control line to the trailer by means of the service brake control with a single failure in the towing vehicle service brake system as specified in S5.7.1.
(c) [Reserved]
S5.8 Emergency brakes for trailers. Each trailer shall meet the requirements of S5.8.1 through S5.8.3.
S5.8.1 Emergency braking capability. Each trailer other than a trailer converter dolly shall have a parking brake system that conforms to S5.6 and that applies with the force specified in S5.6.1 or S5.6.2 when the air pressure in the supply line is at atmospheric pressure. A trailer converter dolly shall have, at the manufacturer's option—
(a) A parking brake system that conforms to S5.6 and that applies with the force specified in S5.6.1 or S5.6.2 when the air pressure in the supply line is at atmospheric pressure, or
(b) An emergency system that automatically applies the service brakes when the service reservoir is at any pressure above 20 lb/in 2 and the supply line is at atmospheric pressure. However, any agricultural commodity trailer, heavy hauler trailer, or pulpwood trailer shall meet the requirements of S5.8.1 or, at the option of the manufacturer, the requirements of § 393.43 of this title.
S5.8.2 Supply line pressure retention. Any single leakage type failure in the service brake system (except for a failure of the supply line, a valve directly connected to the supply line or a component of a brake chamber housing) shall not result in the pressure in the supply line falling below 70 psi, measured at the forward trailer supply coupling. A trailer shall meet the above supply line pressure retention requirement with its brake system connected to the trailer test rig shown in Figure 1, with the reservoirs of the trailer and test rig initially pressurized to 100 psi and the regulator of the trailer test rig set at 100 psi; except that a trailer equipped with an air-applied, mechanically-held parking brake system and not designed to tow a vehicle equipped with air brakes, at the manufacturer's option, may meet the requirements of S5.8.4 rather than those of S5.8.2 and S5.8.3.
S5.8.3 Automatic application of parking brakes. With an initial reservoir system pressure of 100 psi and initial supply line pressure of 100 psi, and if designed to tow a vehicle equipped with air brakes, with a 50 cubic inch test reservoir connected to the rear supply line coupling, and with any subsequent single leakage type failure in any other brake system, of a part designed to contain compressed air or brake fluid (consistent with the parenthetical phrase specified in S5.6.3.1), whenever the air pressure in the supply line is 70 psi or higher, the parking brakes shall not provide any brake retardation as a result of complete or partial automatic application of the parking brakes.
S5.8.4 Automatic application of air-applied, mechanically held parking brakes. With its brake system connected to the supply line portion of the trailer test rig (Figure 1) and the regulator of the trailer test rig set at 100 psi, and with any single leakage type failure in the service brake system (except for a failure of the supply line, a valve directly connected to the supply line or a component of a brake chamber, but including failure of any common diaphragm), the parking brakes shall not provide any brake retardation as a result of complete or partial automatic application of the parking brakes.
S5.9 Final inspection. Inspect the service brake system for the condition of adjustment and for the brake indicator display in accordance with S5.1.8 and S5.2.2.
S6. Conditions. The requirements of S5 shall be met by a vehicle when it is tested according to the conditions set in this S6, without replacing any brake system part or making any adjustments to the brake system except as specified. Unless otherwise specified, where a range of conditions is specified, the vehicle must be capable of meeting the requirements at all points within the range. On vehicles equipped with automatic brake adjusters, the automatic brake adjusters must remain activated at all times. Compliance of vehicles manufactured in two or more stages may, at the option of the final-stage manufacturer, be demonstrated to comply with this standard by adherence to the instructions of the incomplete vehicle manufacturer provided with the vehicle in accordance with § 568.4(a)(7)(ii) and § 568.5 of title 49 of the Code of Federal Regulations.
S6.1 Road test conditions.
S6.1.1 Except as otherwise specified, the vehicle is loaded to its GVWR, distributed proportionally to its GAWRs. During the burnish procedure specified in S6.1.8, truck tractors shall be loaded to their GVWR, by coupling them to an unbraked flatbed semitrailer, which semitrailer shall be loaded so that the weight of the tractor-trailer combination equals the GVWR of the truck tractor. The load on the unbraked flatbed semitrailer shall be located so that the truck tractor's wheels do not lock during burnish.
S6.1.2 The inflation pressure is as specified by the vehicle manufacturer for the GVWR.
S6.1.3 Unless otherwise specified, the transmission selector control is in neutral or the clutch is disengaged during all decelerations and during static parking brake tests.
S6.1.4 All vehicle openings (doors, windows, hood, trunk, cargo doors, etc.) are in a closed position except as required for instrumentation purposes.
S6.1.5 The ambient temperature is between 32 °F. and 100 °F.
S6.1.6 The wind velocity is zero.
S6.1.7 Unless otherwise specified, stopping tests are conducted on a 12-foot wide level, straight roadway having a peak friction coefficient of 1.02. For road tests in S5.3, the vehicle is aligned in the center of the roadway at the beginning of a stop. Peak friction coefficient is measured using an ASTM F2493 standard reference test tire in accordance with ASTM E1337-19 (incorporated by reference, see § 571.5), at a speed of 40 mph, without water delivery for the surface with PFC of 1.02, and with water delivery for the surface with PFC of 0.55.
S6.1.8 For vehicles with parking brake systems not utilizing the service brake friction elements, burnish the friction elements of such systems prior to the parking brake test according to the manufacturer's recommendations. For vehicles with parking brake systems utilizing the service brake friction elements, burnish the brakes as follows: With the transmission in the highest gear appropriate for a speed of 40 mph, make 500 snubs between 40 mph and 20 mph at a deceleration rate of 10 f.p.s.p.s., or at the vehicle's maximum deceleration rate if less than 10 f.p.s.p.s. Except where an adjustment is specified, after each brake application accelerate to 40 mph and maintain that speed until making the next brake application at a point 1 mile from the initial point of the previous brake application. If the vehicle cannot attain a speed of 40 mph in 1 mile, continue to accelerate until the vehicle reaches 40 mph or until the vehicle has traveled 1.5 miles from the initial point of the previous brake application, whichever occurs first. Any automatic pressure limiting valve is in use to limit pressure as designed. The brakes may be adjusted up to three times during the burnish procedure, at intervals specified by the vehicle manufacturer, and may be adjusted at the conclusion of the burnishing, in accordance with the vehicle manufacturer's recommendation.
S6.1.9 Static parking brake tests for a semitrailer are conducted with the front-end supported by an unbraked dolly. The weight of the dolly is included as part of the trailer load.
S6.1.10 In a test other than a static parking test, a truck tractor is tested at its GVWR by coupling it to an unbraked flatbed semi-trailer (hereafter, control trailer) as specified in S6.1.10.2 to S6.1.10.4.
S6.1.10.1 [Reserved]
S6.1.10.2 The center of gravity height of the ballast on the loaded control trailer shall be less than 24 inches above the top of the tractor's fifth wheel.
S6.1.10.3 The control trailer has a single axle with a GAWR of 18,000 pounds and a length, measured from the transverse centerline of the axle to the centerline of the kingpin, of 258 ±6 inches.
S6.1.10.4 The control trailer is loaded so that its axle is loaded at 4,500 pounds and the tractor is loaded to its GVWR, loaded above the kingpin only, with the tractor's fifth wheel adjusted so that the load on each axle measured at the tire-ground interface is most nearly proportional to the axles' respective GAWRs, without exceeding the GAWR of the tractor's axle or axles or control trailer's axle.
S6.1.11 Special drive conditions. A vehicle equipped with an interlocking axle system or a front wheel drive system that is engaged and disengaged by the driver is tested with the system disengaged.
S6.1.12 Liftable axles. A vehicle with a liftable axle is tested at GVWR with the liftable axle down and at unloaded vehicle weight with the liftable axle up.
S6.1.13 Trailer test rig.
The trailer test rig shown in Figure 1 is calibrated in accordance with the calibration curves shown in Figure 3. For the requirements of S5.3.3.1 and S5.3.4.1, the pressure in the trailer test rig reservoir is initially set at 100 psi for actuation tests and 95 psi for release tests.
S6.1.14 In testing the emergency braking system of towing vehicles under S5.7.3(a), the hose(s) is vented to the atmosphere at any time not less than 1 second and not more than 1 minute before the emergency stop begins, while the vehicle is moving at the speed from which the stop is to be made and any manual control for the towing vehicle protection system is in the position to supply air and brake control signals to the vehicle being towed. No brake application is made from the time the line(s) is vented until the emergency stop begins and no manual operation of the parking brake system or towing vehicle protection system occurs from the time the line(s) is vented until the stop is completed.
S6.1.15 Initial brake temperature. Unless otherwise specified, the initial brake temperature is not less than 150 °F and not more than 200 °F.
S6.1.16 Thermocouples.
The brake temperature is measured by plug-type thermocouples installed in the approximate center of the facing length and width of the most heavily loaded shoe or disc pad, one per brake, as shown in Figure 2. A second thermocouple may be installed at the beginning of the test sequence if the lining wear is expected to reach a point causing the first thermocouple to contact the rubbing surface of a drum or rotor. The second thermocouple shall be installed at a depth of .080 inch and located within 1 inch circumferentially of the thermocouple installed at .040 inch depth. For centergrooved shoes or pads, thermocouples are installed within one-eighth of an inch to one-quarter of an inch of the groove and as close to the center as possible.
S6.1.17 Selection of compliance options. Where manufacturer options are specified, the manufacturer shall select the option by the time it certifies the vehicle and may not thereafter select a different option for the vehicle. Each manufacturer shall, upon request from the National Highway Traffic Safety Administration, provide information regarding which of the compliance options it has selected for a particular vehicle or make/model.
S6.2 Dynamometer test conditions.
S6.2.1 The dynamometer inertia for each wheel is equivalent to the load on the wheel with the axle loaded to its GAWR. For a vehicle having additional GAWRs specified for operation at reduced speeds, the GAWR used is that specified for a speed of 50 mph, or, at the option of the manufacturer, any speed greater than 50 mph.
S6.2.2 The ambient temperature is between 75 °F. and 100 °F.
S6.2.3 Air at ambient temperature is directed uniformly and continuously over the brake drum or disc at a velocity of 2,200 feet per minute.
S6.2.4 The temperature of each brake is measured by a single plug-type thermocouple installed in the center of the lining surface of the most heavily loaded shoe or pad as shown in Figure 2. The thermocouple is outside any center groove.
S6.2.5 The rate of brake drum or disc rotation on a dynamometer corresponding to the rate of rotation on a vehicle at a given speed is calculated by assuming a tire radius equal to the static loaded radius specified by the tire manufacturer.
S6.2.6 Brakes are burnished before testing as follows: place the brake assembly on an inertia dynamometer and adjust the brake as recommended by the vehicle manufacturer. Make 200 stops from 40 mph at a deceleration of 10 f.p.s.p.s., with an initial brake temperature on each stop of not less than 315 °F and not more than 385 °F. Make 200 additional stops from 40 mph at a deceleration of 10 f.p.s.p.s. with an initial brake temperature on each stop of not less than 450 °F and not more than 550 °F. The brakes may be adjusted up to three times during the burnish procedure, at intervals specified by the vehicle manufacturer, and may be adjusted at the conclusion of the burnishing, in accordance with the vehicle manufacturer's recommendation.
S6.2.7 The brake temperature is increased to a specified level by conducting one or more stops from 40 m.p.h. at a deceleration of 10 f.p.s.p.s. The brake temperature is decreased to a specified level by rotating the drum or disc at a constant 30 m.p.h.
Table I—Stopping Sequence
Table II—Stopping Distance in Feet
Note:
(1) Loaded and Unloaded Buses.
(2) Loaded Single-Unit Trucks.
(3) Loaded Tractors with Two Axles; or with Three Axles and a GVWR of 70,000 lbs. or less; or with Four or More Axles and a GVWR of 85,000 lbs. or less. Tested with an Unbraked Control Trailer.
(4) Loaded Tractors with Three Axles and a GVWR greater than 70,000 lbs.; or with Four or More Axles and a GVWR greater than 85,000 lbs. Tested with an Unbraked Control Trailer.
(5) Unloaded Single-Unit Trucks.
(6) Unloaded Tractors (Bobtail).
(7) All Vehicles except Tractors, Loaded and Unloaded.
(8) Unloaded Tractors (Bobtail).
Table IIa—Stopping Distance in Feet: Optional Requirements for: (1) Three-Axle Tractors With a Front Axle That Has a GAWR of 14,600 Pounds or Less, and With Two Rear Drive Axles That Have a Combined GAWR of 45,000 Pounds or Less, Manufactured Before August 1, 2011; and (2) All Other Tractors Manufactured Before August 1, 2013
Note: (1) Loaded and unloaded buses; (2) Loaded single unit trucks; (3) Unloaded truck tractors and single unit trucks; (4) Loaded truck tractors tested with an unbraked control trailer; (5) All vehicles except truck tractors; (6) Unloaded truck tractors.
Table III—Brake Retardation Force
Table V—Brake Chamber Rated Volumes
§ 571.122   Standard No. 122; Motorcycle brake systems.
S1. Scope. This standard specifies requirements for motorcycle service brake systems and, where applicable, associated parking brake systems.
S2. Purpose. The purpose of the standard is to ensure safe motorcycle braking performance under normal and emergency riding conditions.
S3. Application. This standard applies to category 3-1 motorcycles, category 3-2 motorcycles, category 3-3 motorcycles, and category 3-4 motorcycles manufactured on and after September 1, 2014. This standard applies to category 3-5 motorcycles manufactured on and after September 1, 2015. At the manufacturer's option, any motorcycle manufactured on or after October 23, 2012 may comply with this standard.
S4. Definitions.
Antilock brake system or ABS means a system which senses wheel slip and automatically modulates the pressure producing the braking forces at the wheel(s) to limit the degree of wheel slip.
Baseline test means a stop or a series of stops carried out in order to confirm the performance of the brake prior to subjecting it to a further test such as the heating procedure or wet brake stop.
Brake means those parts of the brake system where the forces opposing the movement of the motorcycle are developed.
Brake system means the combination of parts consisting of the control, the brake, and the components that provide the functional link between the control and the brake, but excluding the engine, whose function it is to progressively reduce the speed of a moving motorcycle, bring it to a halt, and keep it stationary when halted.
Category 3-1 motorcycle means a two-wheeled motorcycle with an engine cylinder capacity in the case of a thermic engine not exceeding 50 cubic centimeters (cm 3 ) and whatever the means of propulsion a maximum design speed not exceeding 50 kilometers per hour (km/h).
Category 3-2 motorcycle means a three-wheeled motorcycle of any wheel arrangement with an engine cylinder capacity in the case of a thermic engine not exceeding 50 cm 3 and whatever the means of propulsion a maximum design speed not exceeding 50 km/h.
Category 3-3 motorcycle means a two-wheeled motorcycle with an engine cylinder capacity in the case of a thermic engine exceeding 50 cm 3 or whatever the means of propulsion a maximum design speed exceeding 50 km/h.
Category 3-4 motorcycle means a motorcycle manufactured with three wheels asymmetrically arranged in relation to the longitudinal median plane with an engine cylinder capacity in the case of a thermic engine exceeding 50 cm 3 or whatever the means of propulsion a maximum design speed exceeding 50 km/h. (This category definition is intended to include motorcycles with sidecars.)
Category 3-5 motorcycle means a motorcycle manufactured with three wheels symmetrically arranged in relation to the longitudinal median plane with an engine cylinder capacity in the case of a thermic engine exceeding 50 cm 3 or whatever the means of propulsion a maximum design speed exceeding 50 km/h.
Combined brake system or CBS means:
(a) For motorcycle categories 3-1 and 3-3: a service brake system where at least two brakes on different wheels are actuated by the operation of a single control.
(b) For motorcycle categories 3-2 and 3-5: a service brake system where the brakes on all wheels are actuated by the operation of a single control.
(c) For motorcycle category 3-4: a service brake system where the brakes on at least the front and rear wheels are actuated by the operation of a single control. (If the rear wheel and the asymmetrical wheel are braked by the same brake system, this is regarded as the rear brake.)
Control means the part actuated directly by the rider in order to supply and regulate the energy required for braking the motorcycle.
Driver mass means the nominal mass of a driver that equals 75 kg (68 kg occupant mass plus 7kg of luggage mass).
Engine disconnected means when the engine is no longer internally connected to the driving wheel(s), i.e., the clutch is disengaged and/or the transmission is in neutral.
Gross vehicle mass means the maximum mass of the fully laden solo vehicle, based on its construction and design performances, as declared by the manufacturer.
Initial brake temperature means the temperature of the hottest brake before any brake application.
Laden means the gross vehicle mass.
Lightly loaded means mass in running order plus 15 kg for test equipment, or the laden condition, whichever is less. In the case of ABS tests on a low friction surface (paragraphs S6.9.4 to S6.9.7), the mass for test equipment is increased to 30 kg to account for outriggers.
Mass in running order means the sum of unladen vehicle mass and driver mass.
Peak braking coefficient or PBC means the measure of tire-to-road surface friction based on the maximum deceleration of a rolling tire.
Power-assisted braking system means a brake system in which the energy necessary to produce the braking force is supplied by the physical effort of the rider assisted by one or more energy supplying devices, for example vacuum assisted (with vacuum booster).
Secondary brake system means the second service brake system on a motorcycle equipped with a combined brake system.
Service brake system means a brake system which is used for slowing the motorcycle when in motion.
Sidecar means a one-wheeled vehicle that is attached to the side of a motorcycle.
Single brake system means a brake system which acts on only one axle.
Split service brake system or SSBS means a brake system that operates the brakes on all wheels, consisting of two or more subsystems actuated by a single control designed so that a single failure in any subsystem (such as a leakage type failure of a hydraulic subsystem) does not impair the operation of any other subsystem.
Stopping distance means the distance traveled by the motorcycle from the point the rider begins to actuate the brake control to the point at which the motorcycle reaches full stop. For tests where simultaneous actuation of two controls is specified, the distance traveled is taken from the point the first control is actuated.
Test speed means the motorcycle speed measured the moment the rider begins to actuate the brake control. For tests where simultaneous actuation of two controls is specified, the motorcycle speed is taken from the moment the first control is actuated.
Unladen vehicle mass means the nominal mass of a complete vehicle as determined by the following criteria:
(a) Mass of the vehicle with bodywork and all factory fitted equipment, electrical and auxiliary equipment for normal operation of vehicle, including liquids, tools, fire extinguisher, standard spare parts, chocks and spare wheel, if fitted.
(b) The fuel tanks filled to at least 90 percent of rated capacity and the other liquid containing systems (except those for used water) to 100 percent of the capacity specified by the manufacturer.
Vmax means either the speed attainable by accelerating at a maximum rate from a standing start for a distance of 1.6 km on a level surface, with the vehicle lightly loaded, or the speed measured in accordance with International Organization for Standardization (ISO) 7117:1995(E) (incorporated by reference; see § 571.5).
Wheel lock means the condition that occurs when there is 100 percent wheel slip.
S5. General requirements.
S5.1 Brake system requirements. Each motorcycle shall meet each of the test requirements specified for a motorcycle of its category and for those brake features on the motorcycle.
S5.1.1 Service brake system control operation. Each motorcycle shall have a configuration that enables a rider to actuate the service brake system control while seated in the normal driving position and with both hands on the steering control.
S5.1.2 Secondary brake system control operation. Each motorcycle shall have a configuration that enables a rider to actuate the secondary brake system control while seated in the normal driving position and with at least one hand on the steering control.
S5.1.3 Parking brake system.
(a) If a parking brake system is fitted, it shall hold the motorcycle stationary on the slope prescribed in S6.8.2. The parking brake system shall:
(1) have a control which is separate from the service brake system controls; and
(2) be held in the locked position by solely mechanical means.
(b) Each motorcycle equipped with a parking brake shall have a configuration that enables a rider to be able to actuate the parking brake system while seated in the normal driving position.
S5.1.4 Two-wheeled motorcycles of categories 3-1 and 3-3. Each category 3-1 and 3-3 two-wheeled motorcycle shall be equipped with either two separate service brake systems, or a split service brake system, with at least one brake operating on the front wheel and at least one brake operating on the rear wheel.
S5.1.5 Three-wheeled motorcycles of category 3-4. Each category 3-4 motorcycle shall comply with the brake system requirements in S5.1.4. A brake on the asymmetric wheel (with respect to the longitudinal axis) is not required.
S5.1.6 Three-wheeled motorcycles of category 3-2. Each category 3-2 motorcycle shall be equipped with a parking brake system plus one of the following service brake systems:
(a) Two separate service brake systems, except CBS, which, when applied together, operate the brakes on all wheels; or
(b) A split service brake system; or
(c) A CBS that operates the brake on all wheels and a secondary brake system which may be the parking brake system.
S5.1.7 Three-wheeled motorcycles of categories 3-5. Each category 3-5 motorcycle shall be equipped with:
(a) A parking brake system; and
(b) A foot actuated service brake system which operates the brakes on all wheels by way of either:
(1) A split service brake system; or
(2) A CBS and a secondary brake system, which may be the parking brake system.
S5.1.8 Two separate service brake systems. For motorcycles where two separate service brake systems are installed, the systems may share a common brake, if a failure in one system does not affect the performance of the other.
S5.1.9 Hydraulic service brake system. For motorcycles that use hydraulic fluid for brake force transmission, the master cylinder shall:
(a) Have a sealed, covered, separate reservoir for each brake system; and
(b) Have a minimum reservoir capacity equivalent to 1.5 times the total fluid displacement required to satisfy the new to fully worn lining condition with the worst case brake adjustment conditions; and
(c) Have a reservoir where the fluid level is visible for checking without removal of the cover.
(d) Have a brake fluid warning statement that reads as follows, in letters at least 3/32 of an inch high: Warning: Clean filler cap before removing. Use only ________ fluid from a sealed container (inserting the recommended type of brake fluid as specified in accordance with 49 CFR 571.116, e.g., “DOT 3”). The lettering shall be:
(1) Permanently affixed, engraved, or embossed;
(2) Located so as to be visible by direct view, either on or within 4 inches of the brake-fluid reservoir filler plug or cap; and
(3) Of a color that contrasts with its background, if it is not engraved or embossed.
S5.1.10 Warning lamps. All warning lamps shall be mounted in the rider's view.
S5.1.10.1 Split service brake system warning lamps.
(a) Each motorcycle that is equipped with a split service brake system shall be fitted with a red warning lamp, which shall be activated:
(1) When there is a hydraulic failure on the application of a force of ≤90 N on the control; or
(2) Without actuation of the brake control, when the brake fluid level in the master cylinder reservoir falls below the greater of:
(i) That which is specified by the manufacturer; or
(ii) That which is less than or equal to half of the fluid reservoir capacity.
(b) To permit function checking, the warning lamp shall be illuminated by the activation of the ignition switch and shall be extinguished when the check has been completed. The warning lamp shall remain on while a failure condition exists whenever the ignition switch is in the “on” position.
(c) Each indicator lamp shall have the legend “Brake Failure” on or adjacent to it in letters not less than 3/32 of an inch high that shall be legible to the driver in daylight when lighted.
S5.1.10.2 Antilock brake system warning lamps.
(a) Each motorcycle equipped with an ABS system shall be fitted with a yellow warning lamp. The lamp shall be activated whenever there is a malfunction that affects the generation or transmission of signals in the motorcycle's ABS system.
(b) To permit function checking, the warning lamp shall be illuminated by the activation of the ignition switch and extinguished when the check has been completed. The warning lamp shall remain on while a failure condition exists whenever the ignition switch is in the “on” position.
(c) The warning lamp shall be labeled in accordance with the specifications in Table 3 of Standard No. 123 (49 CFR 571.123) for “ABS Malfunction” (Item No. 13).
S5.2 Durability.
S5.2.1 Compensation for wear. Wear of the brakes shall be compensated for by means of a system of automatic or manual adjustment.
S5.2.2 Notice of wear. The friction material thickness shall either be visible without disassembly, or where the friction material is not visible, wear shall be assessed by means of a device designed for that purpose.
S5.2.3 Testing. During all the tests in this standard and on their completion, there shall be no friction material detachment and no leakage of brake fluid.
S5.3 Measurement of dynamic performance. There are two ways in which brake system performance is measured. The particular method to be used is specified in the respective tests in S6.
S5.3.1 Stopping distance.
(a) Based on the basic equations of motion:
(b) To calculate the corrected stopping distance using the actual vehicle test speed, the following formula is used:
This equation is only valid when the actual test speed (Va) is within ±5 km/h of the specified test speed (Vs).
S5.3.2 Continuous deceleration recording. The other method used to measure performance is the continuous recording of the vehicle instantaneous deceleration from the moment a force is applied to the brake control until the end of the stop.
S6. Test conditions, procedures and performance requirements.
S6.1 General.
S6.1.1 Test surfaces.
S6.1.1.1 High friction surface. A high friction surface is used for all dynamic brake tests excluding the ABS tests where a low-friction surface is specified. The high-friction surface test area is a clean, dry and level surface, with a gradient of ≤1 percent. The high-friction surface has a peak braking coefficient (PBC) of 1.02.
S6.1.1.2 Low-friction surface. A low-friction surface is used for ABS tests where a low-friction surface is specified. The low-friction surface test area is a clean and level surface, which may be wet or dry, with a gradient of ≤1 percent. The low-friction surface has a PBC of ≤0.50.
S6.1.1.3 Measurement of PBC. The PBC is measured using the ASTM F2493 standard reference test tire, in accordance with ASTM E1337-19, at a speed of 64 km/h (incorporated by reference; see § 571.5).
S6.1.1.4 Parking brake system tests. The specified test slope has a clean and dry surface that does not deform under the weight of the motorcycle.
S6.1.1.5 Test lane width. For two-wheeled motorcycles (motorcycle categories 3-1 and 3-3) the test lane width is 2.5 meters. For three-wheeled motorcycles (motorcycle categories 3-2, 3-4 and 3-5) the test lane width is 2.5 meters plus the vehicle width.
S6.1.2 Ambient temperature. The ambient temperature is between 4 °C and 45 °C.
S6.1.3 Wind speed. The wind speed is not more than 5 meters per second (m/s).
S6.1.4 Test speed tolerance. The test speed tolerance is ±5 km/h. In the event of the actual test speed deviating from the specified test speed (but within the ±5 km/h tolerance), the actual stopping distance is corrected using the formula in S5.3.1(b).
S6.1.5 Automatic transmission. Motorcycles with automatic transmission shall meet all test requirements—whether they are for “engine connected” or “engine disconnected.” If an automatic transmission has a neutral position, the neutral position is selected for tests where “engine disconnected” is specified.
S6.1.6 Vehicle position and wheel lock. The vehicle is positioned in the center of the test lane for the beginning of each stop. Stops are made without the vehicle wheels passing outside the applicable test lane and without wheel lock.
S6.1.7 Test sequence. Test sequence is as specified in Table 1.
S6.2 Preparation.
S6.2.1 Engine idle speed. The engine idle speed is set to the manufacturer's specification.
S6.2.2 Tire pressures. The tires are inflated to the manufacturer's specification for the vehicle loading condition for the test.
S6.2.3 Control application points and direction. For a hand control lever, the input force (F) is applied on the control lever's forward surface perpendicular to the axis of the lever fulcrum and its outermost point on the plane along which the control lever rotates (see Figure 1). The input force is applied to a point located 50 millimeters (mm) from the outermost point of the control lever, measured along the axis between the central axis of the fulcrum of the lever and its outermost point. For a foot control pedal, the input force is applied to the center of, and at right angles to, the control pedal.
S6.2.4 Brake temperature measurement. The brake temperature is measured on the approximate center of the facing length and width of the most heavily loaded shoe or disc pad, one per brake, using a plug-type thermocouple that is embedded in the friction material, as shown in Figure 2.
S6.2.5 Burnishing procedure. The vehicle brakes are burnished prior to evaluating performance.
S6.2.5.1 Vehicle condition.
(a) Vehicle lightly loaded.
(b) Engine disconnected.
S6.2.5.2 Conditions and procedure.
(a) Initial brake temperature. Initial brake temperature before each brake application is ≤100 °C.
(b) Test speed.
(1) Initial speed: 50 km/h or 0.8 Vmax, whichever is lower.
(2) Final speed = 5 to 10 km/h.
(c) Brake application. Each service brake system control actuated separately.
(d) Vehicle deceleration.
(1) Single front brake system only:
(i) 3.0-3.5 meters per second squared (m/s 2 ) for motorcycle categories 3-3 and 3-4
(ii) 1.5-2.0 m/s 2 for motorcycle categories 3-1 and 3-2
(2) Single rear brake system only: 1.5-2.0 m/s 2
(3) CBS or split service brake system, and category 3-5: 3.5-4.0 m/s 2
(e) Number of decelerations. There shall be 100 decelerations per brake system.
(f) For the first stop, accelerate the vehicle to the initial speed and then actuate the brake control under the conditions specified until the final speed is reached. Then reaccelerate to the initial speed and maintain that speed until the brake temperature falls to the specified initial value. When these conditions are met, reapply the brake as specified. Repeat this procedure for the number of specified decelerations. After burnishing, adjust the brakes in accordance with the manufacturer's recommendations.
S6.3 Dry stop test—single brake control actuated.
S6.3.1 Vehicle condition.
(a) The test is applicable to all motorcycle categories.
(b) Laden. For vehicles fitted with CBS and split service brake system, the vehicle is tested in the lightly loaded condition in addition to the laden condition.
(c) Engine disconnected.
S6.3.2 Test conditions and procedure.
(a) Initial brake temperature. Initial brake temperature is ≥55 °C and ≤100 °C.
(b) Test speed.
(1) Motorcycle categories 3-1 and 3-2: 40 km/h or 0.9 Vmax, whichever is lower.
(2) Motorcycle categories 3-3, 3-4 and 3-5: 60 km/h or 0.9 Vmax, whichever is lower.
(c) Brake application. Each service brake system control actuated separately.
(d) Brake actuation force.
(1) Hand control: ≤200 N.
(2) Foot control:
(i) ≤350 N for motorcycle categories 3-1, 3-2, 3-3, and 3-4.
(ii) ≤500 N for motorcycle category 3-5.
(e) Number of stops: until the vehicle meets the performance requirements, with a maximum of 6 stops.
(f) For each stop, accelerate the vehicle to the test speed and then actuate the brake control under the conditions specified in this paragraph.
S6.3.3 Performance requirements. When the brakes are tested in accordance with the test procedure set out in paragraph S6.3.2., the stopping distance shall be as specified in column 2 of Table 2.
S6.4 Dry stop test—all service brake controls actuated.
S6.4.1 Vehicle condition.
(a) The test is applicable to motorcycle categories 3-3, 3-4 and 3-5.
(b) Lightly loaded.
(c) Engine disconnected.
S6.4.2 Test conditions and procedure.
(a) Initial brake temperature. Initial brake temperature is ≥55 °C and ≤100 °C.
(b) Test speed. Test speed is 100 km/h or 0.9 Vmax, whichever is lower.
(c) Brake application. Simultaneous actuation of both service brake system controls, if so equipped, or of the single service brake system control in the case of a service brake system that operates on all wheels.
(d) Brake actuation force.
(1) Hand control: ≤250 N.
(2) Foot control:
(i) ≤400 N for motorcycle categories 3-3 and 3-4.
(ii) ≤500 N for motorcycle category 3-5.
(e) Number of stops: until the vehicle meets the performance requirements, with a maximum of 6 stops.
(f) For each stop, accelerate the vehicle to the test speed and then actuate the brake control under the conditions specified in this paragraph.
S6.4.3 Performance requirements. When the brakes are tested in accordance with the test procedure set out in paragraph S6.4.2., the stopping distance (S) shall be S ≤0.0060 V 2 (where V is the specified test speed in km/h and S is the required stopping distance in meters).
S6.5 High speed test.
S6.5.1 Vehicle condition.
(a) The test is applicable to motorcycle categories 3-3, 3-4 and 3-5.
(b) Test is not required for vehicles with Vmax ≤125 km/h.
(c) Lightly loaded.
(d) Engine connected (clutch engaged) with the transmission in the highest gear.
S6.5.2 Test conditions and procedure.
(a) Initial brake temperature. Initial brake temperature is ≥55 °C and ≤100 °C.
(b) Test speed.
(1) Test speed is 0.8 Vmax for motorcycles with Vmax >125 km/h and <200 km/h.
(2) Test speed is 160 km/h for motorcycles with Vmax ≥200 km/h.
(c) Brake application. Simultaneous actuation of both service brake system controls, if so equipped, or of the single service brake system control in the case of a service brake system that operates on all wheels.
(d) Brake actuation force.
(1) Hand control: ≤200 N.
(2) Foot control:
(i) ≤350 N for motorcycle categories 3-3 and 3-4.
(ii) ≤500 N for motorcycle category 3-5.
(e) Number of stops: until the vehicle meets the performance requirements, with a maximum of 6 stops.
(f) For each stop, accelerate the vehicle to the test speed and then actuate the brake control(s) under the conditions specified in this paragraph.
S6.5.3 Performance requirements. When the brakes are tested in accordance with the test procedure set out in paragraph S6.5.2, the stopping distance (S) shall be ≤0.1 V + 0.0067 V 2 (where V is the specified test speed in km/h and S is the required stopping distance in meters).
S6.6 Wet brake test.
S6.6.1 General information.
(a) The test is comprised of two parts that are carried out consecutively for each brake system:
(1) A baseline test based on the dry stop test—single brake control actuated (S6.3).
(2) A single wet brake stop using the same test parameters as in (1), but with the brake(s) being continuously sprayed with water while the test is conducted in order to measure the brakes' performance in wet conditions.
(b) The test is not applicable to parking brake systems unless it is the secondary brake.
(c) Drum brakes or fully enclosed disc brakes are excluded from this test unless ventilation or open inspection ports are present.
(d) This test requires the vehicle to be fitted with instrumentation that gives a continuous recording of brake control force and vehicle deceleration.
S6.6.2 Vehicle condition.
(a) The test is applicable to all motorcycle categories.
(b) Laden. For vehicles fitted with CBS and split service brake system, the vehicle is tested in the lightly loaded condition in addition to the laden condition.
(c) Engine disconnected.
(d) Each brake is fitted with water spray equipment as shown in Figure 3.
(1) Disc brakes—sketch of water spray equipment. The disc brake water spray equipment is installed as follows:
(i) Water is sprayed onto each brake with a flow rate of 15 liters/hr. The water is equally distributed on each side of the rotor.
(ii) If the surface of the rotor has any shielding, the spray is applied 45° prior to the shield.
(iii) If it is not possible to locate the spray in the position shown on the sketch, or if the spray coincides with a brake ventilation hole or similar, the spray nozzle may be advanced by an additional 90° maximum from the edge of the pad, using the same radius.
(2) Drum brakes with ventilation and open inspection ports. The water spray equipment is installed as follows:
(i) Water is sprayed equally onto both sides of the drum brake assembly (on the stationary back plate and on the rotating drum) with a flow rate of 15 liters/hr.
(ii) The spray nozzles are positioned two thirds of the distance from the outer circumference of the rotating drum to the wheel hub center.
(iii) The nozzle position is >15° from the edge of any opening in the drum back plate.
S6.6.3 Baseline test—test conditions and procedure.
(a) The test in paragraph S6.3 (dry stop test—single brake control actuated) is carried out for each brake system but with the brake control force that results in a vehicle deceleration of 2.5-3.0 m/s 2 , and the following is determined:
(1) The average brake control force measured when the vehicle is traveling between 80 percent and 10 percent of the specified test speed.
(2) The average vehicle deceleration in the period 0.5 to 1.0 seconds after the point of actuation of the brake control.
(3) The maximum vehicle deceleration during the complete stop but excluding the final 0.5 seconds.
(b) Conduct 3 baseline stops and average the values obtained in (1), (2), and (3).
S6.6.4 Wet brake test—test conditions and procedure.
(a) The vehicle is ridden at the test speed used in the baseline test set out in S6.6.3 with the water spray equipment operating on the brake(s) to be tested and with no application of the brake system.
(b) After a distance of ≥500 m, apply the average brake control force determined in the baseline test for the brake system being tested.
(c) Measure the average vehicle deceleration in the period 0.5 to 1.0 seconds after the point of actuation of the brake control.
(d) Measure the maximum vehicle deceleration during the complete stop but excluding the final 0.5 seconds.
S6.6.5 Performance requirements. When the brakes are tested in accordance with the test procedure set out in paragraph S6.6.4, the wet brake deceleration performance shall be:
(a) The value measured in paragraph S6.6.4(c) shall be ≥60 percent of the average deceleration values recorded in the baseline test in paragraph S6.6.3(a)(2), i.e., in the period 0.5 to 1.0 seconds after the point of actuation of the brake control; and
(b) The value measured in S6.6.4(d) shall be ≤120 percent of the average deceleration values recorded in the baseline test S6.6.3(a)(3), i.e., during the complete stop but excluding the final 0.5 seconds.
S6.7 Heat fade test.
S6.7.1 General information.
(a) The test comprises three parts that are carried out consecutively for each brake system:
(1) A baseline test using the dry stop test—single brake control actuated (S6.3).
(2) A heating procedure which consists of a series of repeated stops in order to heat the brake(s).
(3) A hot brake stop using the dry stop test—single brake control actuated (S6.3), to measure the brake's performance after the heating procedure.
(b) The test is applicable to motorcycle categories 3-3, 3-4 and 3-5.
(c) The test is not applicable to parking brake systems and secondary service brake systems.
(d) All stops are carried out with the motorcycle laden.
(e) The heating procedure requires the motorcycle to be fitted with instrumentation that gives a continuous recording of brake control force and vehicle deceleration.
S6.7.2 Baseline test.
S6.7.2.1 Vehicle condition—baseline test. Engine disconnected.
S6.7.2.2 Test conditions and procedure—baseline test.
(a) Initial brake temperature. Initial brake temperature is ≥55 °C and ≤100 °C.
(b) Test speed. Test speed is 60 km/h or 0.9 Vmax, whichever is the lower.
(c) Brake application. Each service brake system control is actuated separately.
(d) Brake actuation force.
(1) Hand control: ≤200 N.
(2) Foot control:
(i) ≤350 N for motorcycle categories 3-3 and 3-4.
(ii) ≤500 N for motorcycle category 3-5.
(e) Accelerate the vehicle to the test speed, actuate the brake control under the conditions specified and record the control force required to achieve the vehicle braking performance specified in the table to S6.3.3 (Table 2).
S6.7.3 Heating procedure.
S6.7.3.1 Vehicle condition—heating procedure. Engine transmission:
(a) From the specified test speed to 50 per cent specified test speed: connected, with the highest appropriate gear selected such that the engine speed remains above the manufacturer's specified idle speed.
(b) From 50 per cent specified test speed to standstill: disconnected.
S6.7.3.2 Test conditions and procedure—heating procedure.
(a) Initial brake temperature. Initial brake temperature is (prior to first stop only) ≥55 °C and ≤100 °C.
(b) Test speed.
(1) Single brake system, front wheel braking only: 100 km/h or 0.7 Vmax, whichever is the lower.
(2) Single brake system, rear wheel braking only: 80 km/h or 0.7 Vmax, whichever is the lower.
(3) CBS or split service brake system: 100 km/h or 0.7 Vmax, whichever is the lower.
(c) Brake application. Each service brake system control actuated separately.
(d) Brake actuation force.
(1) For the first stop: The constant control force that achieves a vehicle deceleration rate of 3.0—3.5 m/s 2 while the vehicle is decelerating between 80 percent and 10 percent of the specified speed.
(2) For the remaining stops:
(i) The same constant brake control force as used for the first stop.
(ii) Number of stops: 10.
(iii) Interval between stops: 1000 m.
(e) Carry out a stop to the conditions specified in this paragraph and then immediately use maximum acceleration to reach the specified speed and maintain that speed until the next stop is made.
S6.7.4 Hot brake stop—test conditions and procedure. Perform a single stop under the conditions used in the baseline test (S6.7.2) for the brake system that has been heated during the procedure in accordance with S6.7.3. This stop is carried out within one minute of the completion of the procedure set out in S6.7.3 with a brake control application force less than or equal to the force used during the test set out in S6.7.2.
S6.7.5 Performance requirements. When the brakes are tested in accordance with the test procedure set out in S6.7.4, the stopping distance S 2 shall be ≤1.67 S 1 −0.67 × 0.1V,
S6.8 Parking brake system test—for motorcycles with parking brakes.
S6.8.1 Vehicle condition.
(a) The test is applicable to motorcycle categories 3-2, 3-4 and 3-5.
(b) Laden.
(c) Engine disconnected.
S6.8.2 Test conditions and procedure.
(a) Initial brake temperature. Initial brake temperature is ≤100 °C.
(b) Test surface gradient. Test surface gradient is equal to 18 percent.
(c) Brake actuation force.
(1) Hand control: ≤400 N.
(2) Foot control: ≤500 N.
(d) For the first part of the test, park the vehicle on the test surface gradient facing up the slope by applying the parking brake system under the conditions specified in this paragraph. If the vehicle remains stationary, start the measurement of the test period.
(e) The vehicle must remain stationary to the limits of traction of the braked wheels.
(f) On completion of the test with vehicle facing up the gradient, repeat the same test procedure with the vehicle facing down the gradient.
S6.8.3 Performance requirements. When tested in accordance with the test procedure set out in S6.8.2, the parking brake system shall hold the vehicle stationary for 5 minutes when the vehicle is both facing up and facing down the gradient.
S6.9 ABS tests.
S6.9.1 General.
(a) The tests are only applicable to the ABS fitted on motorcycle categories 3-1 and 3-3.
(b) The tests are to confirm the performance of brake systems equipped with ABS and their performance in the event of ABS electrical failure.
(c) Fully cycling means that the anti-lock system is repeatedly modulating the brake force to prevent the directly controlled wheels from locking.
(d) Wheel-lock is allowed as long as the stability of the vehicle is not affected to the extent that it requires the operator to release the control or causes a vehicle wheel to pass outside the test lane.
(e) The test series comprises the individual tests in Table 3, which may be carried out in any order.
S6.9.2 Vehicle condition.
(a) Lightly loaded.
(b) Engine disconnected.
S6.9.3 Stops on a high friction surface.
S6.9.3.1 Test conditions and procedure.
(a) Initial brake temperature. Initial brake temperature is ≥55 °C and ≤100 °C.
(b) Test speed. Test speed is 60 km/h or 0.9 Vmax, whichever is lower.
(c) Brake application. Simultaneous actuation of both service brake system controls, if so equipped, or of the single service brake control in the case of a service brake system that operates on all wheels.
(d) Brake actuation force. The force applied is that which is necessary to ensure that the ABS will cycle fully throughout each stop, down to 10 km/h.
(e) If one wheel is not equipped with ABS, the control for the service brake on that wheel is actuated with a force that is lower than the force that will cause the wheel to lock.
(f) Number of stops: until the vehicle meets the performance requirements, with a maximum of 6 stops.
(g) For each stop, accelerate the vehicle to the test speed and then actuate the brake control under the conditions specified in this paragraph.
S6.9.3.2 Performance requirements. When the brakes are tested in accordance with the test procedures referred to in S6.9.3.1:
(a) The stopping distance (S) shall be ≤0.0063 V 2 (where V is the specified test speed in km/h and S is the required stopping distance in meters); and
(b) there shall be no wheel lock beyond that allowed for in paragraph S6.9.1(d), and the vehicle wheels shall stay within the test lane.
S6.9.4 Stops on a low friction surface.
S6.9.4.1 Test conditions and procedure. As set out in S6.9.3.1, but using the low friction surface instead of the high friction one.
S6.9.4.2 Performance requirements. When the brakes are tested in accordance with the test procedures set out in S6.9.4.1:
(a) the stopping distance (S) shall be ≤0.0056 V 2 /P (where V is the specified test speed in km/h, P is the peak braking coefficient and S is the required stopping distance in meters); and
(b) there shall be no wheel lock beyond that allowed for in paragraph S6.9.1(d), and the vehicle wheels shall stay within the test lane.
S6.9.5 Wheel lock checks on high and low friction surfaces.
S6.9.5.1 Test conditions and procedure.
(a) Test surfaces. High friction or low friction surface, as applicable.
(b) Initial brake temperature. Initial brake temperature is ≥55 °C and ≤100 °C.
(c) Test speed.
(1) On the high friction surface: 80 km/h or 0.8 Vmax, whichever is lower.
(2) On the low friction surface: 60 km/h or 0.8 Vmax, whichever is lower.
(d) Brake application.
(1) Each service brake system control actuated separately.
(2) Where ABS is fitted to both brake systems, simultaneous actuation of both brake controls in addition to (1).
(e) Brake actuation force. The force applied is that which is necessary to ensure that the ABS will cycle fully throughout each stop, down to 10 km/h.
(f) Brake application rate. The brake control actuation force is applied in 0.2-0.5 seconds.
(g) Number of stops: until the vehicle meets the performance requirements, with a maximum of 3 stops.
(h) For each stop, accelerate the vehicle to the test speed and then actuate the brake control under the conditions specified in this paragraph.
S6.9.5.2 Performance requirements. When the brakes are tested in accordance with the test procedures set out in S6.9.5.1, there shall be no wheel lock beyond that allowed for in paragraph S6.9.1(d), and the vehicle wheels shall stay within the test lane.
S6.9.6 Wheel lock check—high to low friction surface transition.
S6.9.6.1 Test conditions and procedure.
(a) Test surfaces. A high friction surface immediately followed by a low friction surface.
(b) Initial brake temperature. Initial brake temperature is ≥55 °C and ≤100 °C.
(c) Test speed. The speed that will result in 50 km/h or 0.5 Vmax, whichever is the lower, at the point where the vehicle passes from the high friction to the low friction surface.
(d) Brake application.
(1) Each service brake system control actuated separately.
(2) Where ABS is fitted to both brake systems, simultaneous actuation of both brake controls in addition to (1).
(e) Brake actuation force. The force applied is that which is necessary to ensure that the ABS will cycle fully throughout each stop, down to 10 km/h.
(f) Number of stops: until the vehicle meets the performance requirements, with a maximum of 3 stops.
(g) For each stop, accelerate the vehicle to the test speed and then actuate the brake control before the vehicle reaches the transition from one friction surface to the other.
S6.9.6.2 Performance requirements. When the brakes are tested in accordance with the test procedures set out in S6.9.6.1, there shall be no wheel lock beyond that allowed for in paragraph S6.9.1(d), and the vehicle wheels shall stay within the test lane.
S6.9.7 Wheel lock check—low to high friction surface transition.
S6.9.7.1 Test conditions and procedure.
(a) Test surfaces. A low friction surface immediately followed by a high friction surface with a PBC ≥0.90.
(b) Initial brake temperature. Initial brake temperature is ≥55 °C and ≤100 °C.
(c) Test speed. The speed that will result in 50 km/h or 0.5 Vmax, whichever is the lower, at the point where the vehicle passes from the low friction to the high friction surface.
(d) Brake application.
(1) Each service brake system control applied separately.
(2) Where ABS is fitted to both brake systems, simultaneous application of both brake controls in addition to (1).
(e) Brake actuation force. The force applied is that which is necessary to ensure that the ABS will cycle fully throughout each stop, down to 10 km/h.
(f) Number of stops: until the vehicle meets the performance requirements, with a maximum of 3 stops.
(g) For each stop, accelerate the vehicle to the test speed and then actuate the brake control before the vehicle reaches the transition from one friction surface to the other.
(h) Record the vehicle's continuous deceleration.
S6.9.7.2 Performance requirements. When the brakes are tested in accordance with the test procedures set out in S6.9.7.1:
(a) There shall be no wheel lock beyond that allowed for in paragraph S6.9.1(d), and the vehicle wheels shall stay within the test lane, and
(b) within 1 second of the rear wheel passing the transition point between the low and high friction surfaces, the vehicle deceleration shall increase.
S6.9.8 Stops with an ABS electrical failure.
S6.9.8.1 Test conditions and procedure. With the ABS electrical system disabled, carry out the test set out in S6.3 (dry stop test—single brake control actuated) applying the conditions relevant to the brake system and vehicle being tested.
S6.9.8.2 Performance requirements. When the brakes are tested in accordance with the test procedure set out in S6.9.8.1:
(a) The system shall comply with the failure warning requirements of S5.1.10.2; and
(b) the minimum requirements for stopping distance shall be as specified in column 2 under the heading “Single brake system, rear wheel(s) braking only” in Table 2.
S6.10 Partial failure test—for split service brake systems.
S6.10.1 General information.
(a) The test is only applicable to vehicles that are equipped with split service brake systems.
(b) The test is to confirm the performance of the remaining subsystem in the event of a hydraulic system leakage failure.
S6.10.2 Vehicle condition.
(a) The test is applicable to motorcycle categories 3-3, 3-4 and 3-5.
(b) Lightly loaded.
(c) Engine disconnected.
S6.10.3 Test conditions and procedure.
(a) Initial brake temperature. Initial brake temperature is ≥55 °C and ≤100 °C.
(b) Test speed. Test speed is 50 km/h and 100 km/h or 0.8 Vmax, whichever is lower.
(c) Brake actuation force.
(1) Hand control: ≤250 N.
(2) Foot control: ≤400 N.
(d) Number of stops: until the vehicle meets the performance requirements, with a maximum of 6 stops for each test speed.
(e) Alter the service brake system to induce a complete loss of braking in any one subsystem. Then, for each stop, accelerate the vehicle to the test speed and then actuate the brake control under the conditions specified in this paragraph.
(f) Repeat the test for each subsystem.
S6.10.4 Performance requirements. When the brakes are tested in accordance with the test procedure set out in S6.10.3:
(a) the system shall comply with the failure warning requirements set out in paragraph S5.1.10.1; and
(b) the stopping distance (S) shall be ≤0.1 V + 0.0117 V 2 (where V is the specified test speed in km/h and S is the required stopping distance in meters).
S6.11 Power-assisted braking system failure test.
S6.11.1 General information.
(a) The test is not conducted when the vehicle is equipped with another separate service brake system.
(b) The test is to confirm the performance of the service brake system in the event of failure of the power assistance.
S6.11.2 Test conditions and procedure. Carry out the test set out in S6.3.3 (dry stop test—single brake control actuated) for each service brake system with the power assistance disabled.
S6.11.3 Performance requirements. When the brakes are tested in accordance with the test procedure set out in S6.11.2, the stopping distance shall be as specified in column 2 of Table 4. Note that if the power assistance may be activated by more than one control, the above performance shall be achieved when each control is actuated separately.
Table 1—Test Sequence
Table 2—Performance Requirements, Dry Stop Test—Single Brake Control Actuated
Table 3—ABS Tests
Table 4—Performance Requirements, Power-Assisted Braking System Failure Test
§ 571.122a   Standard No. 122; Motorcycle brake systems.
S1. Scope. This standard specifies performance requirements for motorcycle brake systems.
S2. Purpose. The purpose of the standard is to insure safe motorcycle braking performance under normal and emergency conditions.
S3. Application. This standard applies to motorcycles. However, this standard does not apply to motorcycles certified to comply with § 571.122.
S4. Definitions.
Braking interval means the distance measured from the start of one brake application to the start of the next brake application.
Initial brake temperature means the temperature of the hottest service brake of the vehicle 0.2 mile before any brake application.
Skid number means the frictional resistance of a pavement measured in accordance with ASTM E274-70 (incorporated by reference, see § 571.5) at 40 mph, omitting water delivery as specified in paragraphs 7.1 and 7.2 of that method.
Stopping distance means the distance traveled by a vehicle from the start of the brake application to the point where the vehicle stops.
Split service brake system means a brake system consisting of two or more subsystems actuated by a single control designed so that a leakage-type failure of a pressure component in a single subsystem (except structural failure of a housing that is common to all subsystems) shall not impair the operation of the other subsystem(s).
S5. Requirements. Each motorcycle shall meet the following requirements under the conditions specified in S6, when tested according to the procedures and in the sequence specified in S7. Corresponding test procedures of S7 are indicated in parentheses. If a motorcycle is incapable of attaining a specified speed, its service brakes shall be capable of stopping the vehicle from the multiple of 5 m.p.h. that is 4 m.p.h. to 8 m.p.h. less than the speed attainable in 1 mile, within stopping distances that do not exceed the stopping distances specified in Table 1.
S5.1 Required equipment—split service brake system. Each motorcycle shall have either a split service brake system or two independently actuated service brake systems.
S5.1.1 Mechanical service brake system. Failure of any component in a mechanical service brake system shall not result in a loss of braking ability in the other service brake system on the vehicle.
S5.1.2 Hydraulic service brake system. A leakage failure in a hydraulic service brake system shall not result in a loss of braking ability in the other service brake system on the vehicle. Each motorcycle equipped with a hydraulic brake system shall have the equipment specified in S5.1.2.1 and S5.1.2.2.
S5.1.2.1 Master cylinder reservoirs. Each master cylinder shall have a separate reservoir for each brake circuit, with each reservoir filler opening having its own cover, seal, and cover retention device. Each reservoir shall have a minimum capacity equivalent to one and one-half times the total fluid displacement resulting when all the wheel cylinders or caliper pistons serviced by the reservoir move from a new lining, fully retracted position to a fully worn, fully applied position. Where adjustment is a factor, the worst condition of adjustment shall be used for this measurement.
S5.1.2.2 Reservoir labeling. Each motorcycle shall have a brake fluid warning statement that reads as follows, in letters at least three thirty-seconds of an inch high:
Warning: Clean filler cap before removing. Use only ______ fluid from a sealed container. (Inserting the recommended type of brake fluid as specified in 49 CFR 571.116, e.g., DOT 3.)
The lettering shall be:
(a) Permanently affixed, engraved, or embossed;
(b) Located so as to be visible by direct view, either on or within 4 inches of the brake-fluid reservoir filler plug or cap; and
(c) Of a color that contrasts with its background, if it is not engraved or embossed.
S5.1.3 Split service brake system. In addition to the equipment required by S5.1.2 each motorcycle equipped with a split service brake system shall have a failure indicator lamp as specified in S5.1.3.1.
S5.1.3.1 Failure indicator lamp.
(a) One or more electrically operated service brake system failure indicator lamps that is mounted in front of and in clear view of the driver, and that is activated—
(1) In the event of pressure failure in any part of the service brake system, other than a structural failure of either a brake master cylinder body in a split integral body type master cylinder system or a service brake system failure indicator body, before or upon application of not more than 20 pounds of pedal force upon the service brake.
(2) Without the application of pedal force, when the level of brake fluid in a master cylinder reservoir drops to less than the recommended safe level specified by the manufacturer or to less than one-half the fluid reservoir capacity, whichever is the greater.
(b) All failure indicator lamps shall be activated when the ignition switch is turned from the “off” to the “on” or to the “start” position.
(c) Except for the momentary activation required by S5.1.3.1(b), each indicator lamp, once activated, shall remain activated as long as the condition exists, whenever the ignition switch is in the “on” position. An indicator lamp activated when the ignition is turned to the “start” position shall be deactivated upon return of the switch to the “on” position unless a failure exists in the service brake system.
(d) Each indicator lamp shall have a red lens with the legend “Brake Failure” on or adjacent to it in letters not less than three thirty-seconds of an inch high that shall be legible to the driver in daylight when lighted.
S5.1.4 Parking brake. Each three-wheeled motorcycle shall be equipped with a parking brake of a friction type with a solely mechanical means to retain engagement.
S5.1.5 Other requirements. The brake system shall be installed so that the lining thickness of drum brake shoes may be visually inspected, either directly or by use of a mirror without removing the drums, and so that disc brake friction lining thickness may be visually inspected without removing the pads.
S5.2 Service brake system—first (preburnish) effectiveness.
S5.2.1 Service brake system. The service brakes shall be capable of stopping the motorcycle from 30 m.p.h. and 60 m.p.h. within stopping distances which do not exceed the stopping distances specified in Column I of Table I (S7.3.1).
S5.2.2 Partial service brake system. Each independently actuated service brake system on each motorcycle shall be capable of stopping the motorcycle from 30 m.p.h. and 60 m.p.h. within stopping distances which do not exceed the stopping distances specified in Column II of Table I (S7.3.2).
S5.3 Service brake system—second effectiveness. The service brakes shall be capable of stopping the motorcycle from 30 m.p.h., 60 m.p.h., 80 m.p.h., and the multiple of 5 m.p.h. that is 4 m.p.h. to 8 m.p.h. less than the speed attainable in 1 mile if this speed is 95 m.p.h. or greater, within stopping distances that do not exceed the stopping distances specified in Column III of Table I (S7.5).
S5.4 Service brake system—fade and recovery. These requirements do not apply to a motor-driven cycle whose speed attainable in 1 mile is 30 m.p.h. or less.
S5.4.1 Baseline check—minimum and maximum pedal forces. The pedal and lever forces used in establishing the fade baseline check average shall be within the limits specified in S6.10 (S7.6.1).
S5.4.2 Fade. Each motorcycle shall be capable of making 10 fade stops from 60 m.p.h. at not less than 15 f.p.s.p.s. for each stop (S7.6.2).
S5.4.3 Fade recovery. Each motorcycle shall be capable of making five recovery stops with a pedal force that does not exceed 400 Newtons (90 pounds), and a hand lever force that does not exceed 245 Newtons (55 pounds) for any of the first four recovery stops and that for the fifth recovery stop, is within, plus 89 Newtons (20 pounds) and minus 44 Newtons (10 pounds) of the fade test baseline check average force (S7.6.3), but not less than 0 Newtons (0 pounds).
S5.5 Service brake system—final effectiveness. These requirements do not apply to a motor-driven cycle whose speed attainable in 1 mile is 30 mph or less.
S5.5.1 Service brake system. The service brakes shall be capable of stopping the motorcycle in a manner that complies with S5.3 (S7.8.1).
S5.5.2 Hydraulic service brake system—partial failure. In the event of a pressure component leakage failure, other than a structural failure of either a brake master cylinder body in a split integral body type master cylinder system or a service brake system failure indicator body, the remaining portion of the service brake system shall continue to operate and shall be capable of stopping the motorcycle from 30 m.p.h. and 60 m.p.h. within stopping distances that do not exceed the stopping distances specified in Column IV of Table I (S7.8.2).
S5.6 Parking brake system. The parking brake system shall be capable of holding the motorcycle stationary (to the limits of traction of the braked wheels), for 5 minutes, in both forward and reverse directions, on a 30 percent grade, with an applied force of not more than 90 pounds for a foot-operated system and 55 pounds for a hand-operated system (S7.9).
S5.7 Service brake system—water recovery.
S5.7.1 Baseline check. The pedal and lever forces used in establishing the water recovery baseline check average shall be within the limits specified in S6.10 (S7.10.1).
S5.7.2 Water recovery test. Each motorcycle shall be capable of making five recovery stops with a pedal force that does not exceed 400 Newtons (90 pounds), and hand lever force that does not exceed 245 Newtons (55 pounds), for any of the first four recovery stops, and that for the fifth recovery stop, is within, plus 89 Newtons (20 pounds) and minus 44 Newtons (10 pounds) of the water recovery baseline check average force (S7.10.2), but not less than 0 Newtons (0 pounds).
S5.8 Service brake system design durability. Each motorcycle shall be capable of completing all braking requirements of S5 without detachment of brake linings from the shoes or pad, detachment or fracture of any brake system components, or leakage of fluid or lubricant at the wheel cylinder, and master cylinder reservoir cover, seal, or retention device (S7.11).
S6 Test conditions. The requirements of S5 shall be met under the following conditions. Where a range of conditions is specified, the motorcycle shall be capable of meeting the requirements at all points within the range.
S6.1 Vehicle weight. Motorcycle weight is unloaded vehicle weight plus 200 pounds (including driver and instrumentation), with the added weight distributed in the saddle or carrier if so equipped.
S6.2 Tire inflation pressure. Tire inflation pressure is the pressure recommended by the manufacturer for the vehicle weight specified in paragraph S6.1.
S6.3 Transmission. Unless otherwise specified, all stops are made with the clutch disengaged.
S6.4 Engine. Engine idle speed and ignition timing settings are according to the manufacturer's recommendations. If the vehicle is equipped with an adjustable engine speed governor, it is adjusted according to the manufacturer's recommendation.
S6.5 Ambient temperature. The ambient temperature is between 32 °F. and 100 °F.
S6.6 Wind velocity. The wind velocity is zero.
S6.7 Road surface. Road tests are conducted on level roadway having a skid number of 81. The roadway is 8 feet wide for two-wheeled motorcycles, and overall vehicle width plus 5 feet for three-wheeled motorcycles. The parking brake test surface is clean, dry, smooth portland cement concrete.
S6.8 Vehicle position. The motorcycle is aligned in the center of the roadway at the start of each brake application. Stops are made without any part of the motorcycle leaving the roadway and without lockup of any wheel.
S6.9 Thermocouples. The brake temperature is measured by plug-type thermocouples installed in the approximate center of the facing length and width of the most heavily loaded shoe or disc pad, one per brake, as shown in Figure 1.
S6.10 Brake actuation forces. Except for the requirements of the fifth recovery stop in S5.4.3 and S5.7.2 (S7.6.3 and S7.10.2), the hand lever force is not less than 10 Newtons (2.3 pounds) and not more than 245 Newtons (55 pounds) and the foot pedal force is not less than 25 Newtons (5.6 pounds) and not more than 400 Newtons (90 pounds). The point of initial application of the lever forces is 1.2 inches from the end of the brake lever grip. The direction of the force is perpendicular to the handle grip on the plane along which the brake lever rotates, and the point of application of the pedal force is the center of the foot contact pad of the brake pedal. The direction of the force is perpendicular to the foot contact pad on the plane along which the brake pedal rotates, as shown in Figure 2.
S7. Test procedures and sequence. Each motorcycle shall be capable of meeting all the requirements of this standard when tested according to the procedures and in the sequence set forth below without replacing any brake system part, or making any adjustments to the brake system other than as permitted in S7.4. A motorcycle shall be deemed to comply with S5.2, S5.3 and S5.5 if at least one of the stops specified in S7.3, S7.5 and S7.8 is made within the stopping distances specified in Table I.
S7.1 Braking warming. If the initial brake temperature for the first stop in a test procedure (other than S7.10) has not been reached, heat the brakes to the initial brake temperature by making up to 10 stops from 30 m.p.h. at a deceleration of not more than 10 f.p.s.p.s. On independently operated brake systems, the coldest brake shall be within 10 °F. of the hottest brake.
S7.2 Pretest instrumentation check. Conduct a general check of test instrumentation by making not more than 10 stops from a speed of not more than 30 m.p.h. at a deceleration of not more than 10 f.p.s.p.s. If test instrument repair, replacement, or adjustment is necessary, make not more than 10 additional stops after such repair, replacement or adjustment.
S7.3 Service brake system—first ( preburnished ) effectiveness test.
S7.3.1 Service brake system. Make six stops from 30 m.p.h. and then six stops from 60 m.p.h. with an initial brake temperature between 130 °F. and 150 °F.
S7.3.2 Partial service brake system. For a motorcycle with two independently actuated service brake systems, repeat S7.3.1 using each service brake system individually.
S7.4 Service brake system—burnish procedure. Burnish the brakes by making 200 stops from 30 m.p.h. at 12 f.p.s.p.s. The braking interval shall be either the distance necessary to reduce the initial brake temperature to between 130 °F. and 150 °F. or 1 mile, whichever occurs first. Accelerate at maximum rate to 30 m.p.h. immediately after each stop and maintain that speed until making the next stop. After burnishing adjust the brakes in accordance with the manufacturer's recommendation.
S7.5 Service brake system—second effectiveness test. Repeat S7.3.1. Then, make four stops from 80 m.p.h. and four stops from the multiple of 5 m.p.h. that is 4 m.p.h. to 8 m.p.h. less than the speed attainable in 1 mile if that speed is 95 m.p.h. or greater.
S7.6 Service brake system—fade and recovery test. These requirements do not apply to a motor-driven cycle whose speed attainable in 1 mile is 30 m.p.h. or less.
S7.6.1 Baseline check stops. Make three stops from 30 m.p.h. at 10 to 11 f.p.s.p.s. for each stop. Compute the average of the maximum brake pedal forces and the maximum brake lever forces required for the three stops.
S7.6.2 Fade stops. Make 10 stops from 60 m.p.h. at not less than 15 f.p.s.p.s. for each stop. The initial brake temperature before the first brake application shall be between 130 °F. and 150 °F. Initial brake temperatures before brake applications for subsequent stops shall be those occurring at the distance intervals. Attain the required deceleration as quickly as possible and maintain at least this rate for not less than three-fourths of the total stopping distance for each stop. The interval between the starts of service brake applications shall be 0.4 mile. Drive 1 mile at 30 m.p.h. after the last fade stop and immediately conduct the recovery test specified in S7.6.3.
S7.6.3 Recovery test. Make five stops from 30 m.p.h. at 10 to 11 f.p.s.p.s. for each stop. The braking interval shall not be more than 1 mile. Immediately after each stop accelerate at maximum rate to 30 m.p.h. and maintain that speed until making the next stop.
S7.7 Service brake system—reburnish. Repeat S7.4 except make 35 burnish stops instead of 200 stops. Brakes may be adjusted after reburnish if no tools are used. These requirements do not apply to a motor-driven cycle whose speed attainable in 1 mile is 30 m.p.h. or less.
S7.8 Service brake system—final effectiveness test. These requirements do not apply to a motor-driven cycle whose speed attainable in 1 mile is 30 m.p.h. or less.
S7.8.1 Service brake system. Repeat S7.5 including S7.3.1.
S7.8.2 Partial service brake system test. Alter the service brake system on three-wheeled motorcycles to induce a complete loss of braking in any one subsystem. Determine the line pressure or pedal force necessary to cause the brake system failure indicator to operate. Make six stops from 30 m.p.h. and then six stops from 60 m.p.h. with an initial brake temperature between 130 °F. and 150 °F. Repeat for each subsystem. Determine that the brake failure indicator is operating when the master cylinder fluid level is less than the level specified in S5.1.3.1(a)(2), and that it complies with S5.1.3.1(c). Check for proper operation with each reservoir in turn at a low level. Restore the service brake system to normal at completion of this test.
S7.9 Parking brake test. Starting with an initial brake temperature of not more than 150 °F., drive the motorcycle downhill on the 30 percent grade with the longitudinal axis of the motorcycle in the direction of the grade. Apply the service brakes with a force not exceeding 90 pounds to stop the motorcycle and place the transmission in neutral. Apply the parking brake by exerting a force not exceeding those specified in S5.6. Release the service brake and allow the motorcycle to remain at rest (to the limit of traction of the braked wheels) for 5 minutes. Repeat the test with the motorcycle parked in the reversed (uphill) position on the grade.
S7.10 Service brake system—water recovery test.
S7.10.1 Baseline check stops. Make three stops from 30 m.p.h. at 10 to 11 f.p.s.p.s. for each stop. Compute the average of the maximum brake pedal forces and of the maximum brake lever forces required for the three stops.
S7.10.2 Wet brake recovery stops. Completely immerse the rear brake assembly of the motorcycle in water for 2 minutes with the brake fully released. Next completely immerse the front brake assembly of the motorcycle in water for 2 minutes with the brake fully released. Perform the entire wetting procedure in not more than 7 minutes. Immediately after removal of the front brake from water, accelerate at a maximum rate to 30 mi/h without a brake application. Immediately upon reaching that speed make five stops, each from 30 mi/h at 10 to 11 ft/s 2 for each stop. After each stop (except the last) accelerate the motorcycle immediately at a maximum rate to 30 mi/h and begin the next stop.
S7.11 Final inspection. Upon completion of all the tests inspect the brake system in an assembled condition, for compliance with the brake lining inspection requirements. Disassemble all brakes and inspect:
(a) The entire brake system for detachment or fracture of any component.
(b) Brake linings for detachment from the shoe or pad.
(c) Wheel cylinder, master cylinder, and axle seals for fluid or lubricant leakage.
(d) Master cylinder for reservoir capacity and retention device.
(e) Master cylinder label for compliance with S5.1.2.2.
Table I—Stopping Distances for Effectiveness, Fade and Partial System Tests
Table II—Brake Test Sequence and Requirements
§ 571.123   Standard No. 123; Motorcycle controls and displays.
S1. Scope. This standard specifies requirements for the location, operation, identification, and illumination of motorcycle controls and displays, and requirements for motorcycle stands and footrests.
S2. Purpose. The purpose of this standard is to minimize accidents caused by operator error in responding to the motoring environment, by standardizing certain motorcycle controls and displays.
S3. Application. This standard applies to motorcycles equipped with handlebars, except for motorcycles that are designed, and sold exclusively for use by law enforcement agencies.
S4. Definitions. Clockwise and counterclockwise mean opposing directions of rotation around the following axes, as applicable.
(a) The operational axis of the ignition control, viewed from in front of the ignition lock opening;
(b) The axis of the right handlebar on which the twist-grip throttle is located, viewed from the end of that handlebar;
(c) The axis perpendicular to the center of the speedometer, viewed from the operator's normal eye position.
Scooter means a motorcycle that:
(1) Has a platform for the operator's feet or has integrated footrests, and
(2) Has a step-through architecture, meaning that the part of the vehicle forward of the operator's seat and between the legs of an operator seated in the riding position, is lower in height than the operator's seat.
S5. Requirements.
S5.1. Each motorcycle shall be equipped with a supplemental engine stop control, located and operable as specified in Table 1.
S5.2 Each motorcycle to which this standard applies shall meet the following requirements:
S5.2.1 Control location and operation. If any item of equipment listed in Table 1, Column 1, is provided, the control for such item shall be located as specified in Column 2, and operable as specified in Column 3. Each control located on a right handlebar shall be operable by the operator's right hand throughout its full range without removal of the operator's right hand from the throttle. Each control located on a left handlebar shall be operable by the operator's left hand throughout its full range without removal of the operator's left hand from the handgrip. If a motorcycle with an automatic clutch other than a scooter is equipped with a supplemental rear brake control, the control shall be located on the left handlebar. If a scooter with an automatic clutch is equipped with a supplemental rear brake control, the control shall be on the right side and operable by the operator's right foot. A supplemental control shall provide brake actuation identical to that provided by the required control of Table 1, Item 11, of this Standard. If a motorcycle is equipped with self-proportioning or antilock braking devices utilizing a single control for front and rear brakes, the control shall be located and operable in the same manner as a rear brake control, as specified in Table 1, Item 11, and in this paragraph.
S5.2.2 Display illumination and operation. If an item of equipment listed in Table 2, Column 1, is provided, the display for such item shall be visible to a seated operator under daylight conditions, shall illuminate as specified in Column 2, and shall operate as specified in Column 3.
S5.2.3 Control and display identification. If an item of equipment in Table 3, Column 1, is provided, the item and its operational function shall be identified by:
(a) A symbol substantially in the form shown in Column 3; or
(b) Wording shown in both Column 2 and Column 4; or
(c) A symbol substantially in the form shown in Column 3 and wording shown in both Column 2 and Column 4.
(d) The abbreviations “M.P.H.”, “km/h”, “r/min”, “Hi”, “Lo”, “L”, “R”, and “Res” appearing in Column 2 and Column 4 may be spelled in full. Symbols and words may be provided for equipment items where none are shown in Column 2, Column 3, and Column 4. Any identification provided shall be placed on or adjacent to the control or display position, and shall appear upright to the operator.
S5.2.4 Stands. A stand shall fold rearward and upward if it contacts the ground when the motorcycle is moving forward.
S5.2.5 Footrests. Footrests shall be provided for each designated seating position. Each footrests for a passenger other than an operator shall fold rearward and upward when not in use.
Table 2—Motorcycle Display Illumination and Operation Requirements
§ 571.124   Standard No. 124; Accelerator control systems.
S1. Scope. This standard establishes requirements for the return of a vehicle's throttle to the idle position when the driver removes the actuating force from the accelerator control, or in the event of a severance or disconnection in the accelerator control system.
S2. Purpose. The purpose of this standard is to reduce deaths and injuries resulting from engine overspeed caused by malfunctions in the accelerator control system.
S3. Application. This standard applies to passenger cars, multi-purpose passenger vehicles, trucks, and buses.
S4. Definitions.
S4.1 Driver-operated accelerator control system means all vehicle components, except the fuel metering device, that regulate engine speed in direct response to movement of the driver-operated control and that return the throttle to the idle position upon release of the actuating force.
Fuel metering device means the carburetor, or in the case of certain engines the fuel injector, fuel distributor or fuel injection pump.
Throttle means the component of the fuel metering device that connects to the driver-operated accelerator control system and that by input from the driver-operated accelerator control system controls the engine speed.
Idle position means the position of the throttle at which it first comes in contact with an engine idle speed control appropriate for existing conditions according to the manufacturers' recommendations. These conditions include, but are not limited to, engine speed adjustments for cold engine, air conditioning, and emission control, and the use of throttle setting devices.
Ambient temperature means the surrounding air temperature, at a distance such that it is not significantly affected by heat from the vehicle under test.
S4.2 In the case of vehicles powered by electric motors, the words throttle and idle refer to the motor speed controller and motor shutdown, respectively.
S5. Requirements. The vehicle shall meet the following requirements when the engine is running under any load condition, and at any ambient temperature between −40 degrees Celsius and + 52 degrees Celsius after 12 hours of conditioning at any temperature within that range.
S5.1 There shall be at least two sources of energy capable of returning the throttle to the idle position within the time limit specified by S5.3 from any accelerator position or speed whenever the driver removes the opposing actuating force. In the event of failure of one source of energy by a single severance or disconnection, the throttle shall return to the idle position within the time limits specified by S5.3, from any accelerator position or speed whenever the driver removes the opposing actuating force.
S5.2 The throttle shall return to the idle position from any accelerator position or any speed of which the engine is capable whenever any one component of the accelerator control system is disconnected or severed at a single point. The return to idle shall occur within the time limit specified by S5.3, measured either from the time of severance or disconnection or from the first removal of the opposing actuating force by the driver.
S5.3 Except as provided below, maximum time to return to idle position shall be 1 second for vehicles of 4536 kilograms or less GVWR, and 2 seconds for vehicles of more than 4536 kilograms GVWR. Maximum time to return to idle position shall be 3 seconds for any vehicle that is exposed to ambient air at −18 degrees Celsius to −40 degrees Celsius during the test or for any portion of the 12-hour conditioning period.
§ 571.125   Standard No. 125; Warning devices.
S1. Scope. This standard establishes requirements for devices, without self-contained energy sources, that are designed to be carried in motor vehicles and used to warn approaching traffic of the presence of a stopped vehicle, except for devices designed to be permanently affixed to the vehicle.
S2. Purpose. The purpose of this standard is to reduce deaths and injuries due to rear end collisions between moving traffic and disabled vehicles.
S3. Application. This standard applies to devices, without self-contained energy sources, that are designed to be carried in buses and trucks that have a gross vehicle weight rating (GVWR) greater than 10,000 pounds. These devices are used to warn approaching traffic of the presence of a stopped vehicle, except for devices designed to be permanently affixed to the vehicle.
S4. Definitions. Entrance angle means the angle having as its sides the line through the center, and normal to the face, of the object to be tested, and the line from the center of the object to the center of the source of illumination (Figure 2).
Fluorescent means the property of emitting visible light due to the absorption of radiation of a shorter wavelength which may be outside the visible spectrum.
Observation angle means the angle having as its sides the line from the observation point to the center of the object to be tested and the line from the center of that object to the center of the source of illumination (Figure 2).
Reflex reflective means reflective of light in directions close to the direction of incident light, over a wide range of variations in the direction of incident light.
S5. Requirements.
S5.1 Equipment.
S5.1.1 Reflex reflective material and fluorescent material that meet the requirements of this standard shall be affixed to both faces of the warning device. Alternatively, a dual purpose orange fluorescent and red reflective material that meets the requirements of this standard (hereafter referred to as “dual purpose material”) may be affixed to both faces in places of the reflective and fluorescent materials.
S5.1.2 Each warning device shall be protected from damage and deterioration—
(a) By enclosure in an opaque protective reusable container, except that two or three warning devices intended to be sold for use as a set with a single vehicle may be enclosed in a single container; or
(b) By secure attachment to any light-tight, enclosed, and easily accessible compartment of a new motor vehicle with which it is supplied by the vehicle manufacturer.
S5.1.3 The warning device shall be designed to be erected, and replaced in its container, without the use of tools.
S5.1.4 The warning device shall be permanently and legibly marked with:
(a) Name of manufacturer;
(b) Month and year of manufacture, which may be expressed numerically, as “6/72”; and
(c) The symbol DOT, or the statement that the warning device complies with all applicable Federal motor vehicle safety standards.
S5.1.5 Each warning device shall have instructions for its erection and display.
(a) The instructions shall be either indelibly printed on the warning device or attached in such a manner that they cannot be easily removed.
(b) Instructions for each warning device shall include a recommendation that the driver activate the vehicular hazard warning signal lamps before leaving the vehicle to erect the warning device.
(c) Instructions shall include the illustration depicted in Figure 3 indicating recommended positioning.
S5.2 Configuration.
S5.2.1 When the warning device is erected on level ground:
(a) Part of the warning device shall form an equilateral triangle that stands in a plane not more than 10° from the vertical, with the lower edge of the base of the triangle horizontal and not less than 1 inch above the ground.
(b) None of the required portion of the reflective material and fluorescent material shall be obscured by any other part of the warning device except for any portion of the material over which it is necessary to provide fasteners, pivoting beads or other means to allow collapsibility or support of the device. In any event, sufficient reflective and fluorescent material shall be used on the triangle to meet the requirements of S5.4 and S5.5.
S5.2.2 Each of the three sides of the triangular portion of the warning device shall not be less than 17 and not more than 22 inches long, and not less than 2 and not more than 3 inches wide (Figure 1).
S5.2.3 Each face of the triangular portion of the warning device shall have an outer border of red reflex reflective material of uniform width and not less than 0.75 and not more than 1.75 inches wide, and an inner border of orange fluorescent material of uniform width and not less than 1.25 and not more than 1.30 inches wide (Figure 1). However, this requirement shall not apply if the dual purpose material is used.
S5.2.4 Each vertex of the triangular portion of the warning device shall have a radius of not less than 0.25 inch and not more than 0.50 inch.
S5.2.5 All edges shall be rounded or chamfered, as necessary, to reduce the possibility of cutting or harm to the user.
S5.2.6 The device shall consist entirely of the triangular portion and attachments necessary for its support and enclosure, without additional visible shapes or attachments.
S5.3 Color.
S5.3.1 The color of the red reflex reflective material on the warning device shall have the following characteristics, both before and after the warning device has been conditioned in accordance with S6.1, when the source of illumination is a lamp with a tungsten filament operating at 2856° Kelvin color temperature. Expressed in terms of the International Commission on Illumination (CIE) 1931 standard colorimetric observer system (CIE chromaticity diagram, Figure 4), the chromaticity coordinates of the red reflex reflective material shall lie within the region bounded by the spectrum locus and the lines on the diagram defined by the following equations:
S5.3.2 The color of the orange fluorescent material on the warning device shall have the following characteristics, both before and after the warning device has been conditioned in accordance with S6.1, when the source of illumination is a 150-watt high pressure xenon compact arc lamp. Expressed in terms of the International Commission on Illumination (CIE) 1931 standard colorimetric observer system, the chromaticity coordinates of the orange fluorescent material shall lie within the region bounded by the spectrum locus and the lines on the diagram defined by the following equations:
The 150-watt high pressure xenon compact arc lamp shall illuminate the sample using the unmodified spectrum at an angle of incidence of 45° and an angle of observation of 90°. If dual purpose material is being tested, it shall be illuminated by a 150-watt high pressure xenon compact arc lamp, whose light is diffused by an integrating sphere.
S5.4 Reflectivity. When the red reflex reflective material on the warning device is tested in accordance with S6.2, both before and after the warning device has been conditioned in accordance with S6.1, its total candlepower per incident foot candle shall be not less than the values specified in Table I for each of the listed entrance angles.
S5.5 Luminance. When the orange fluorescent material on the warning device is tested in accordance with S6.3, both before and after the warning device has been conditioned in accordance with S6.1, it shall have a minimum relative luminance of 25 percent of a flat magnesium oxide surface and a minimum product of that relative luminance and width in inches of 44.
S5.6 Stability. When the warning device is erected on a horizontal brushed concrete surface both with and against the brush marks and subjected to a horizontal wind of 40 miles per hour in any direction for 3 minutes—
(a) No part of it shall slide more than 3 inches from its initial position;
(b) Its triangular portion shall not tilt to a position that is more than 10° from the vertical; and
(c) Its triangular position shall not turn through a horizontal angle of more than 10° in either direction from the initial position.
S5.7 Durability. When the warning device is conditioned in accordance with S6.1, no part of the warning device shall become warped or separated from the rest of the warning device.
S6. Test Procedures.
S6.1 Conditions.
S6.1.1 Submit the warning device to the following conditioning sequence, returning the device after each step in the sequence to ambient air at 68 °F. for at least 2 hours.
(a) Minus 40 °F. for 16 hours in a circulating air chamber using ambient air which would have not less than 30 percent and not more than 70 percent relative humidity at 70 °F.;
(b) 150 °F. for 16 hours in a circulating air oven using ambient air which would have not less than 30 percent and not more than 70 percent relative humidity at 70 °F.;
(c) 100 °F. and 90 percent relative humidity for 16 hours;
(d) Salt spray (fog) test in accordance with ASTM B117-64 (incorporated by reference, see § 571.5), except that the test shall be for 4 hours rather than 40 hours; and
(e) Immersion for 2 hours in water at a temperature of 100 °F.
S6.2 Reflectivity Test. Test the red reflex reflective materials as follows:
(a) Unless dual purpose material is used, prevent the orange fluorescent material from affecting the photometric measurement of the reflectivity of the red reflex reflective material, either by separation or masking.
(b) Use a lamp with a tungsten filament operating at 2856° Kelvin color temperature as the source of illumination.
(c) Place the source of illumination 100 feet from the red reflex reflective material (Figure 2).
(d) Place the observation point directly above the source of illumination (Figure 2).
(e) Calculate the total candlepower per incident foot candle of the red reflex reflective material at each of the entrance and observation angles specified in Table 1.
S6.3 Luminance Test. Test the orange fluorescent material as follows:
(a) Unless dual purpose material is used, prevent the red reflex reflective material from affecting the photometric measurement of the luminance of the orange fluorescent material.
(b) Using a 150-watt high pressure xenon compact arc lamp as the light source, illuminate the test sample at an angle of incidence of 45° and an angle of observation of 90°. If dual purpose material is being tested, illuminate the sample diffusely through an integrating sphere.
(c) Measure the luminance of the material at a perpendicular viewing angle, with no ray of the viewing beam more than 5° from the perpendicular to the specimen.
(d) Repeat the procedure for a flat magnesium oxide surface, and compute the quotient (percentage) of the luminance of the material relative to that of the magnesium oxide surface.